Hey guys

I am looking for a new or used fish finder that I can mount on the trolling motor of my 79 tracker. I have one that is extremely old. Basically only goof for depth and temp measurement. I would love to get one of the facing side image units but they are out of my price range. Are there some DSI units that I can get used in my price range? Would any of them have the ability to add the charts/contour maps or gps? Not really sure what is out there that I should be looking for and not sure what is in my price but I do not want to go over 200 for sure

Thanks

T