If you're serious about fishing, get one. Take the time to learn how to read and understand what you're looking at. The important thing is not seeing fish on it, but knowing where the fish will be because you know what's in the water.

It will show you depth changes, rock, grass, trees. All these things are important for finding fish. Especially temperature. If you can't afford a model with built in temp. go to Wal-Mart and buy a digital meat thermometer. They are about $10 and give you a pretty accurate water surface temp reading.

I'll give you an example. Myself and a buddy were fishing about a 200 yard stretch of bank. It was mixed with big rock, tullies and some downed wood. My buddy caught 2 fish. I caught 12! Not because I'm a better angler, but because I found about a 50 yard stretch that dropped from 3-4 ft to 12 ft and then to 19 ft all in about a 50 ft stretch from shore . The fish were not relating to the shore cover, but they were holding at those dropoffs.

I used the depth finder to help keep me positioned in 17-19 ft of water and made short casts to 8-12 ft. If you only plan on fishing docks and fixed visible structure, then I would say to save your money.