Anglers on a tight budget know that high-end fish finders start at several thousand dollars - and head north from there. And while the tech available on flagship fish finders from Garmin, Lowrance, and Humminbird is undeniably game-changing, rising interest rates and stagnant salaries mean that plenty of us have to give these luxuries a pass.
But advances in technology mean that electronic wizardry that was cutting edge just a few decades ago is now readily available and remarkably inexpensive. And despite what you might think, even the most budget-friendly fish finders can deliver remarkable performance, if you know where to look.
Unfortunately, at the under-$100 price point you’ll find great fish finders as well as absolute junk.
But if you’re in the market for an inexpensive fish finder, we’re here to help. In this article, you’ll find reviews of the top rated fish finders under $100, as well as a complete buying guide to get you up to speed fast.
Quick glance at the best fish finders under $100:
- Garmin STRIKER 4 - Best Budget-Friendly Transom-Mounted Fish Finder
- Deeper Start - Best Budget-Friendly Castable Fish Finder
- Reelsonar iBobber
- Humminbird PIRANHAMAX 4
- Lowrance HOOK2 4X
Table of Contents (clickable)
- 1 Best Fish Finders Under $100 Reviewed
- 2 Buying Guide: What to Look for in a Budget-Friendly Fish Finder
- 3 What is Sonar?
- 4 What is CHIRP Sonar?
- 5 Our Picks: The Deeper Start and the Garmin STRIKER 4!
Best Fish Finders Under $100 Reviewed
Garmin STRIKER 4 - Best Budget-Friendly Transom-Mounted Fish Finder
Display Size: 3.5” diagonal
Resolution: 480 x 320
Frequencies: 50/77/200 kHz (traditional) and CHIRP (mid and high)
Maximum Depth: ?
Transducer Angles: ?
Target Separation: ?
You might believe that budget-priced fishing electronics just can’t deliver the goods, but Garmin’s STRIKER 4 can set the record straight. Offering powerful CHIRP sonar as well as GPS-enabled waypointing and marking, you’ll be impressed by the high-end tech in this inexpensive fish finder.
This STRIKER sports a 3.5-inch diagonal screen. That’s not a lot of space, and it’s almost certainly smaller than your smartphone. Its resolution is just average, too, offering 480 x 320.
That said, trade-offs need to be made at this price point, and that’s clearly where costs were cut.
The Striker 4’s screen is pretty good on the water, offering reasonable legibility in bright sunlight and clear images that are easy to decipher.
Garmin’s long experience in the auto GPS market has put it leaps and bounds ahead of the competition in terms of ease of use, and the keypad located below the screen is intuitive, simple to learn, and effective. You won’t need to spend a lot of time pouring over the manual, and there’s little chance you’ll be at a loss on the water.
Garmin doesn’t report which transducer it supplies with the STRIKER 4, so we can’t report specs like transducer beam angles, range, or target separation. What we do know about it is that it transmits in both traditional and CHIRP modes, offering 50/77/200 kHz options for the former and high and low options for the latter.
In the real world, you’ll notice a huge difference between the STRIKER 4 and the Deeper Start. Practical depth with the STRIKER 4 is much, much greater, making this a good buy for inshore as well as freshwater anglers.
And that addition of CHIRP-capable sonar puts the STRIKER 4 heads above its rivals.
Because CHIRP offers longer bursts of sonar over a wide, continuous band of frequencies, the detail it returns is nothing short of incredible - even on an inexpensive fish finder.
We don’t know what the exact target separation the STRIKER 4’s transducer is capable of, but in practice, it has no trouble identifying schooling bait above feeding bass.
Add to this that the STRIKER 4 is equipped with precise GPS waypointing and marking, and you’ve got the edge you were looking for. Not only can you mark your launch and potential hazards, you can identify points, humps, depressions, and channels, providing a clear sense of where to fish - and where to skip.
If you fish from a boat, Garmin’s STRIKER 4 is the best option on our list, hands down.
- Powerful traditional and CHIRP sonar
- GPS-enabled waypointing and marking
- Easy to learn and use
- Great real-world performance
- Small screen isn’t bright in full sun
Deeper Start - Best Budget-Friendly Castable Fish Finder
No products found.
No products found.
Maximum depth: 165 feet
Maximum range: 165 feet
Transducer beam angle: 55 and 15 degrees
Frequency: 90 kHz and 290 kHz
Target separation: ???
Compatibility: iOS 12.0 and Android 5.0 forward
Battery life: up to 6 hours
Charging time: 2.5 hours
Castable fish finders are a great option for budget-minded anglers, and the tech has come a long way toward matching conventional offerings. The Deeper Start is the best of its kind, offering better performance than similarly-priced castable fishing electronics.
And as its name suggests, that makes it a great place to start on your hunt for an affordable fish finder.
The Start is designed around pairing with your smartphone or tablet, and as you’d expect, it’s compatible with both iOS and Android. Enabled by your paired device, specifications like image quality, screen size, and effective range are entirely dependent on the smartphone or tablet to which it’s linked.
Better, brighter screens will be much more readable options on the water, and if your smartphone struggles to provide legibility in bright sun, that’s not going to change when you’re fishing. Similarly, devices that employ a more powerful antenna are going to offer greater range with the Start, and it’s impossible for us to say exactly what you can expect on this front.
That said, the specifications inherent to the Start itself are impressive.
Deeper’s Start is equipped with a lithium polymer battery that can last for as long as 6 hours on a single 2.5-hour charge. In the real world, battery life won’t be quite that long, so the Start isn’t going to be capable of all-day operation.
In “simple” mode, the screen is very easy to read for even novice users.
That’s not surprising given the size and weight of this battery, as well as the need for the Start to provide sufficient buoyancy to keep a power source afloat. We’d like to see greater run times, but at this price point, that’s just not realistic.
Essentially, the Deeper Start is a floating, wireless transducer. It broadcasts on two frequencies, 90 kHz and 290 kHz, using the lower to penetrate the water column to a depth of 165 feet and the higher to locate fish and cover like aquatic vegetation.
Two transducer angles are available as well, 55 and 15 degrees, enabling a wider view of the water column or a tighter focus.
When used properly, these two frequencies and transducer angles will give you a much better picture of the bottom, including contours and cover, as well as the presence of fish. Ideally, you should use the low frequency and wide transducer beam angle for bottom scanning, switching to the high frequency and narrow angle to pinpoint fish.
Deeper isn’t reporting the target separation the Start can deliver, meaning that they won’t say exactly how precise it is. Better (i.e. smaller) target separation allows a fish finder to tell the difference between two fish close together, or to identify a bait cluster as well as the fish feeding on it.
Worse target separation makes it more likely that a few small fish close together will register as a large fish to the sonar, and this is certainly an issue for the Start. That’s apparent on the water and in the specs: 290 kHz just isn’t a high-enough frequency to deliver fine detail.
That said, the Start also provides an important detail you need to fish smarter: water temperature. While that may seem trivial, it’s anything but, and from predicting the spawn to recognizing heat stress, just knowing the precise water temp is going to improve your fishing.
One common criticism of fish finders is that they can be hard to learn and use. The Deeper Start’s user interface is easy to use and intuitive, allowing you to adjust the frequency and transducer beam angle without needing to refer to a manual.
The Start offers two screen settings, “simple” and “detailed.”
The “simple” mode is exactly what it sounds like, displaying everything you want if you’re a novice angler or just new to fish finding tech. By contrast, the “detailed” setting provides something more akin to a traditional fish finder, with more information about the bottom composition as well as depths for each fish it locates.
It’s also worth noting that the Start’s app lets you track locations and make notes, enabling you to mark hot spots and record things like which lures and techniques were working.
That’s a cool feature that really can tilt the odds in your favor.
Overall, the Deeper Start is an affordable, effective castable fish finder that’s perfect for anglers fishing from shore or from a pier.
- Easy to use
- Uncomplicated interface makes the Start easy to read and understand
- Good battery life and recharging rate
- Pretty good fish-finding tech
- Target separation is poor, leading to fish finding inaccuracies
- Maximum range can be dramatically shorter than 165 feet
Maximum depth: 135 feet
Minimum depth: 4 feet
Maximum range: 100 feet
Transducer beam angle: 42 degrees
Target separation: ?
Compatibility: iOS 11.0 and later operating systems and Android 6 or later that use Bluetooth Smart (4.0)
Battery life: 10+ hours
Charging time: 120 minutes
ReelSonar’s iBobber is a castable competitor for the Deeper Start, though it’s the less capable of the two options.
Like the Start, the iBobber is a self-contained transducer that pairs with a smartphone or smartwatch. Any device that runs iOS 11 and newer operating systems - or Android 6 or later operating systems - and uses Bluetooth Smart (4.0) will sync with this fish finder.
As you’d expect, image quality, screen brightness, and effective range are dependent on your paired device.
ReelSonar reports a maximum connectivity range of 100 feet. On the water, that’s pretty optimistic, and even devices with powerful antennas will struggle to maintain a Bluetooth connection at more than 50 feet, especially in choppy conditions.
The iBobber is supplied with a rechargeable lithium battery, and the ReelSonar reports a battery life in excess of 10 hours. That’s simply not at all realistic, and real-world numbers are far more likely to be in the neighborhood of 3-5 hours.
That’s a bit shorter than the Start. You should also be aware of two additional issues.
First, recharging is performed by docking the iBobber in a cradle. We’d prefer a system with a direct connection, as the cradle can be a touch finicky. Make sure that the iBobber is seated properly, though, and recharging is relatively fast.
Second, there have also been multiple reports of rapid discharging when not in use, for instance, while driving to the water from home.
ReelSonar doesn’t report the frequency or frequencies the iBobber is capable of, though they do specify a single transducer beam angle of 42 degrees. As a compromise, that’s not a bad angle if you’re limited to a single setting, but the Deeper Start is clearly the better choice in terms of tech.
The iBobber is supposedly able to detect fish, differentiating between those over and under 15 inches by displaying them in different colors (green or orange) and providing size estimates. On the water, the iBobber’s transducer can have trouble differentiating a fish from the background clutter.
On the water, the result will typically be that the iBobber has a hard time differentiating between cover and fish. It will commonly identify several small minnows as a larger fish, or read aquatic vegetation or other cover as fish,, showing you targets where there are none.
Chalk that up to relatively low-frequency transmission as well as a compromise beam angle.
ReelSonar’s user interface is easy to use and intuitive, and if you generally have no trouble operating your smartphone, the iBobber app isn’t going to feel like an uphill climb.
ReelSonar also equips the iBobber with some cool extras like a fish alarm that can be set to notify you when it detects one. That’s a great feature for bank anglers who want to relax and enjoy their time on the water without focusing on fishing first.
The app is capable of GPS marking, a great feature for anglers who want to scout their lakes and ponds for the best spots to fish. And with weather information, a lunar calendar, and a water temperature sensor, you’ll have all the info you need to fish smarter at your fingertips.
Overall, though, I buy fish finders to get a precise picture of the bottom, identify live weed beds and other cover and locate fish. And unfortunately, these are the weakest aspects of the iBobber, hobbled by middling frequencies and a general-purpose transducer beam angle.
For just a few dollars more you can get the Deeper Start, and even anglers on a tight budget should make that investment.
- Easy to use
- Uncomplicated interface
- Poor real-world signal strength
- Sonar can’t tell the difference between fish and other objects
- Battery discharges quickly - and sometimes while not being used
Display Size: 4.3” diagonal
Resolution: 480 x 272
Maximum Depth: 20 ft @ 455 kHz, 600 ft @ 200 kHz
Transducer Angles: 28 degrees and 16 degrees
Target Separation: ?
Humminbird’s PIRANHAMAX 4 is an excellent fish finder for the money, and there’s no question you’ll be impressed. But when head-on against the CHIRP-capable, GPS-enabled Garmin STRIKER 4, it loses ground.
On its own merits, the PIRANHAMAX 4 is no joke. The 4.3” diagonal screen is bigger and brighter than its Garmin rival, though the image quality is just a hair less crisp. It is more readable in direct sun, however.
Its user interface is button driven, simple, and relatively easy to learn and navigate, and in this case, less is definitely more. On high-end Humminbird units, the range of options complicates the UI quite a bit, but the relative simplicity of the PIRANHAMAX 4 doesn’t bear these burdens.
Hummibird supplies the PIRANHAMAX 4 with a dual-frequency transducer, meaning that it broadcasts on both 200 and 455 kHz simultaneously. Those two frequencies provide plenty of fish-finding detail, especially in shallow water (20 feet or less).
You can also select a narrow, 16-degree transducer beam angle to really target fish, or a wider, 28-degree angle to scan the bottom and find likely targets. These are good options for the frequencies the transducer is pushing, and you’ll find the PIRANHAMAX 4 is exceptionally capable on lakes, ponds, and rivers.
Where the otherwise excellent PIRANHAMAX 4 falls short is the lack of CHIRP sonar. And while it broadcasts at a higher frequency than the STRIKER 4, it can’t provide the target separation or detail to overcome the CHIRP advantage, especially not below 20 feet.
And without GPS, it falls even further behind the Garmin in our view. That doesn’t make it a bad fish finder - far from it! - but its tech just can’t compete with the STRIKER 4, dollar for dollar.
- Brighter, bigger screen than the STRIKER 4
- Dual-frequency sonar
- Your choice of two transducer beam angles
- Excellent imaging in shallow water (above 20 feet)
- Easy-to-use UI
- Image quality can’t compete with CHIRP sonar
- No GPS
Display Size: 4.3” diagonal
Frequencies: 200 kHz
Maximum Depth: 500 feet
Transducer Angles: ?
Target Separation: ?
Lowrance’s Hook2 4X is a budget-minded offering that skips the bells and whistles to deliver good performance at a very reasonable price. Overall, we think that it gives too much ground to the STRIKER 4 to be a true competitor, but you won’t be disappointed by what the Hook2 4X has to offer.
Lowrance supplies its fish finders with some of the best screen tech in the industry, and the Hook2 4X benefits from that. And while Lowrance doesn’t report details like nits or pixels, real-world use confirms that the screen is bright and legible, even from relatively obtuse angles.
For my money, it’s better than the Garmin and the Humminbird in this respect.
The user interface is located to the right of the horizontal screen, using push buttons to navigate menus. Like the PIRANHAMAX 4, less is more, fortunately, and the complexity that plagues the higher-end Lowrance lineup is absent from Hook2 4X. The menus are easy to navigate and the UI is more or less intuitive.
The Bullet Skimmer transducer supplied by Lowrance is pretty basic, offering a single frequency of 200 kHz. That provides enough water-punching power to get down to about 500 feet, but the detail isn’t great the deeper you go, and in any case, it simply can’t compete on this front with either the PIRANHAMAX 4 or the STRIKER 4.
The Hook2 4X is GPS-enabled for waypointing and marking, both of which are excellent fishing tools that you really don’t want to be without.
But overall, Garmin and Humminbird offer more bang for your buck and better tech for your dollar. That doesn’t make the Lowrance a bad buy, and you'll be pleased with its performance as long as you don’t run it side-by-side with its competitors.
- Brighter screen than the STRIKER 4 or PIRANHAMAX 4
- Easy-to-use UI
- GPS waypointing and marking
- Image quality can’t compete with CHIRP sonar
- Single frequency sonar can’t compete with better tech
Buying Guide: What to Look for in a Budget-Friendly Fish Finder
In the neighborhood of $100, you’ll find lots of cheap, gimmicky fish finders that don’t deliver performance you’ll appreciate. And one of the common issues with entry-level fishing tech is that the off-brand stuff is typically not waterproof.
That’s simply unacceptable.
Off-brand fish finders like this Lucky aren’t even minimally waterproof.
From rain to high humidity to an accidental splash, your fishing electronics need to be built to tackle the elements, even at this price point.
And while castable fish finders depend on your smartphone, smartwatch, or tablet, transom-mounted electronics like the Garmin, Humminbird, and Lowrance are built with wet environments in mind.
This is essential, and you shouldn’t buy a fish finder that doesn’t have an IPX7 rating (or better).
Screen quality matters a lot in the real world.
Direct sunlight can make a fish finder’s screen difficult to read, and if you’re actively fishing rather than studying your screen, you may be glancing at it from an obtuse angle.
Excellent screens are bright and legible at relatively extreme angles, but you can’t expect miracles at this price point.
What you should demand, however, are readable images that allow you to make full use of your fish finder, and unfortunately, the off-brands aren’t going to deliver on this front.
Garmin, Humminbird, and Lowrance know fishing tech, and the screens they supply on their entry-level models are pretty capable.
Of course, castable fish finders depend on your paired device, so make sure that it’s legible in direct sun!
Experienced anglers will agree that touch screens are much easier to use than push buttons.
But at this price point, that’s not an option you’ll find. Instead, expect push buttons and menus to get the job done.
The good news is that on entry-level models, the range of bells and whistles is reduced, making navigation a slot easier with buttons than it would be on flagship fish finders. That said, there are better and worse, and Garmin almost always has the easiest-to-learn UIs.
What is Sonar?
Even the most basic fishfinder offers pretty amazing technology.
Fishfinders use sonar to detect the bottom and image its shape, as well as identify fish in the water column. Your transducer emits a sound - at far too high a frequency for you to hear - that travels through the water.
These sound waves strike objects like the bottom, or a fish, and bounce.
Your transducer picks up these bouncing sound waves, and the electronics within convert them into images.
Sonar is just sound. It’s beyond the range of human hearing, but in principle, it’s no different than any other noise.
Sound takes the form of a wave, with crests and troughs or peaks and valleys. Higher frequencies pack more of these oscillations into a given span of time than do lower frequencies.
Traditional fishfinding sonar is typically capable of dual-frequency broadcasting and reception, meaning that the transducer can transmit and receive two different frequencies simultaneously.
Typically, this pairing involved a low frequency and a high frequency, offering both water column penetration and high-quality imagining and target separation.
Low frequencies penetrate water better than high frequencies. Fish finders with very low-frequency transducers can “see” through the water better, allowing them greater depth.
The weakness of low frequencies, however, is that every oscillation provides data, and with less crests and troughs per second, they can’t provide as much information as high frequencies.
Think about your mobile phone for a second. It works much the same way, which is why 4G can carry more information - more data per second - than 3G. Higher frequencies equal more information.
High frequencies offer greater detail, allowing your fish finder to “find” fish and tell you their size and location.
They can’t penetrate much water, however, and they can’t tell you much about the bottom, including details like structure and cover.
What is CHIRP Sonar?
CHIRP stands for Compressed High Intensity Radar Pulse, and it’s an improved sonar technique first developed for military applications.
Instead of a short burst or “ping” of sonar at two different frequencies, a CHIRP-capable transducer broadcasts a much longer burst that covers a wide spectrum of frequencies from low to high, covering everything in between.
It transmits much more sound energy into the water than traditional sonar, resulting in more energy returning to the transducer. That gives your fishfinder a lot more information to work with, and it can provide much better imaging quality and accuracy.
AIRMAR, perhaps the world’s leader in transducer tech, says this:
“Traditional marine fishfinders operate at discrete frequencies such as 50 kHz and 200 kHz, use relatively short-duration transmit pulses, and use narrow band sonar transducers. In contrast, Chirp (compressed high-intensity radar pulse) uses a precise sweep pattern of many frequencies within a long-duration transmit pulse from a broadband transducer, so the equivalent sound energy transmitted into the water is 10 to 1,000 times greater than a conventional marine fishfinder. The echo energy returning to the transducer, superior to that generated by a conventional transducer, is then processed by the fishfinder’s DSP (digital signal processing) computer and displayed in ultra-sharp detail on the display. The combination of Chirp, a broadband transducer, and the fish finder’s DSP, results in dramatically better fish and bottom detection, superior depth capability, and significantly better performance at speed.”
GPS-enabled fish finders offer options that you really want on the water, and from waypointing to marking, they can be game-changing.
From pre-season scouting to hazard avoidance, if you have a GPS option at a similar price point, go for it.
All of the fish finders on our shortlist can measure the water temperature, a vital piece of information for anglers.
Transom-mounted fish finders use external batteries as a power source, and run times are virtually unlimited given their minimal draw.
But castable fish finders use internal lithium batteries, and run times can be far shorter than you’d expect.
The numbers offered by manufacturers are almost always highly optimistic, and in the real world, you can cut them in half, if not a third.
Castable fish finders pair with smart devices via a Bluetooth connection, and ideally, you want the longest range you can get.
But realistically, your smart device’s antenna determines the maximum range, but water conditions can have a profound impact on this number. In choppy conditions, expect the range to be much shorter than on calm days.
Our Picks: The Deeper Start and the Garmin STRIKER 4!
Anglers looking for inexpensive fish finders have great options available, if they know where to look. And two of the best choices are the Deeper Start and the Garmin STRIKER 4.
The Deeper Start is the best castable fishfinder under $100, offering a strong Bluetooth connection, excellent real-world range, and full-featured fishing tech. Capable of broadcasting on two frequencies and two transducer beam angles, it provides anglers fishing from shore a great picture of what’s below the surface, including must-have details like water temperature.
It recharges quickly and offers reasonable battery life, too.
And while there are better, more advanced options from Deeper, they’ll cost a bit more.
For anglers looking for an inexpensive, capable transom-mounted fish finder, there’s no better option than the remarkable STRIKER 4 from Garmin.
It pairs a pretty good screen with the best sonar system at this price point, adding GPS to the mix. Supplied with a CHIRP-capable transducer, it simply leaves its competitors in the dust. Its UI is easy to learn and navigate, and overall, it’s just a great buy.
We hope that this article has helped you make the right choice for your needs and budget, and we’d love to hear from you if you have questions or comments.
Please leave a comment below!