If you’re looking for cheap fresh water fish finder with Down Imaging, the Humminbird 346c DI, is one of the best choices you can make. It’s a unit that focuses exclusively on fish finding functions, without having any navigational features that would considerably increase its price.
This fish finder comes with a smaller head unit, having a 3.5-inch diagona screen, 240H X 320V, with a full color and backlit display. It’s quite a capable depth finder, being equipped with Dual Beam Plus sonar and SwitchFire, which allows it to be operated on two frequencies (separately or simultaneously), at 200 kHz / 28° and 455 kHz / 16°, with a depth capability up to 600 ft. The Down Imaging sonar also has two operability modes: 455 kHz / 75°, or 800 kHz / 45°, with a depth capability up to 350 ft. Its power output is 500 Watts (RMS / 4,000 Watts (PTP). The standard transducer of this unit is a Transom XNT-9-DI-T, and comes with a Quick Disconnect mounting kit.
Other significant fish finding options to mention regarding the 346c DI, are the selective FishID+, temperature alarm and Mark Structure on Sonar, which can be very useful for marking fishing spots, even if this unit does not have chartplotting and trackplotting, and the possibility to create and save waypoints.