Basic Fish Locator/Depth Finder for Pontoon Boat

I have a pontoon boat that stays on the same body of water year-round. I am looking to install a fish locator/depth finder that will simply provide the basics (water temp/depth/structure/basic gps). Does anyone have any recommendations without breaking the bank? I would imagine the transducer gets installed to the back toon? Both of my toons have square looking box on them with holes, so I would assume this is the spot for them. Thanks for the help!

Just by chance check around to see if any of your buddies are updating sonars, chances are you will likely get an old unit just sitting around that can be repurposed for noting or little to nothing.   This is what I did with my Dad's pontoon,  found some old Lowrance gear sitting around, X125 to be exact and works like a champ.   zero cost to repurpose other than to re-run ducer cable, and install new wiring.   just a thought good luck.

I had the Hummingbird KVD (Color) model on my pontoon and it worked great.  Had down imaging and side imaging.  I loved it and it was not that expensive.

There are several threads under the fishing equipment forum, search under that forum you should find some useful information.