I have a Garmin 120 fish finder. Low budget, around $119.00, I have had it 2 years, never failed me. Very basic super easy to use. Gives water temp, fish depth, bottom contour, has some other features like shallow water alert, fish alert, battery charge. Not a bad unit, of course its my first one so I may not be the best judge but, I mark fish with it. They may have changed the model number now I think, but its still in the same price range.