Jim,
I just bought the pond prowler from Bass Pro and bought the Hummingbird 586c for $349.  I mounted the transducer to the trolling motor and it works great.  I have only been out once with this set up but the fishfinder worked great in displaying cover.  Hope this helps.

Jim,  I’ve used the Hummingbird Fishin’ Buddy portable fish finder for years.  It has a screw-down clamp that fits just about any boat, or it can be rigged to my float tube or kayak.  It’s pretty durable and fairly reliable—although I use it primarly to determine depth - mainly finding creek channels and drop-offs—and to gauge water temperature in the spring.  I have never really relied on it to locate fish.  Bass Pro has them starting at $129 and going up with additional features.  Good luck!

Jim:  I have had two fish finders in the past 7 years. I just recently purchased a Garmin 140 (about $120 at Academy) and I have been very pleased with the purchase.  It is only B/W, but since I only have a 12V battery which is used for both the trolling motor and fish finder, the Garmin does not draw that much power.  It is easy to mount to the trolling motor (parts included).  When I fish at my father-in-laws place, I also use a 2-Man molded boat and it works just fine. What I like for the cost are:

- Integrated water temp gauge
- Wide and narrow beams
- Ease of use and installation
- 800w

Trolling motor transducer does work. That is what I use. I recently bought a color version Hummingbird 345 C for about $300.

I also have a B/W Eagle model. I use mine to locate humps, ridges, general depth, and water temperature. Only on rare occasions have I targeted suspended fish, found a lure to throw at that depth and caught fish. However, I do recall a day when this happened at Athens NE lake and we wore them out. Those are the days when you feel like the electronics are worth it. We have a member who has side imagining and a trolling motor that will track your path. The trolling motor works off GPS coordinates and can re-trace your steps (boat path) if you are working down a bank and want to go back the exact direction you just came from. 

Jim I bought an eagle fish easy unit.  It is battery operated on 8 D cells.  I got it bass pro shop during their spring fishing show but that was back in 2002.  I believe I paid around $135 for it.  I find them helpful on the larger bodies of water like Six O Ranch to help with structure.  on smaller ponds they become a burden.  it was also helpful in locating schools of crappie   Could be real helpful in locations where Steve and Brian have placed brush piles. 

Now what I did was to make a portable rack for it using PVC pipe.  Just remember to drill a bunch of holes in it to reduce the drag.  With this bracket you are portable to use on any boat in the club.  I hope this helps.

Jim, a depth finder is very helpful on any body of water you are fishing. It serves as your eyes below the surface, which is very useful on unfamiliar waters. It sure beats guessing.

  You are only limited by your budget. Depth finder technology has made leaps and bounds in the last few years. A trolling motor mounted transducer is perfect for small boats. Go to Bass Pro Shops and let the sales rep. know what your doing and the amount your willing to spend. After seeing your options go online and see if you can get a better deal. If not go back and get what you want. ( be sure the person that helped you out initially gets the commission )

I hope this info. helps. I’m doing the same thing you are right now in preparation for spring. Stick with quality manufactures that offer good warraties and service. You get what you pay for.

Jim,
Click the link below and you will see the one I have used for over two years. It’s very portable, runs on AA batteries and is very powerful. I removed the suction cup from the transducer and bolted a clamp to it so that it will clamp to the trolling motor shaft. There are lots of units out there but this one will more than do the job and it keeps things simple.
http://cgi.ebay.com/Humminbird-PiranhaMax-215-Portable-Fishfinder-/120672820794?pt=LH_DefaultDomain_0&hash=item1c18a91e3a

Jim

Take a look at the Humminbird Fishing Buddy series.  I have the 120 and very happy with it.  It comes with a braket that can attach to the side of the boat.  It runs on AA batteries and no drilling/mods to your boat are necessary - transducer is contained in the unit that hangs over your boat.  B&W may be 150 bucks, color may add another 100 to the price.  I use it all the time on club lakes.  Great for water temp, drop offs, structure.  They have them at Bass Pro in Grapevine.

I also use the Hummingbird Fishing Buddy but mine is about 10 years old. Only uses C batteries. It fits in the Bracket on side of boat and is easly removable when when your done fishing. Great for finding water depth and temp and inexpensive compared to others. It will even work on float tubes and Kayaks.

Thanks to everyone for their comments, advice and input.  As usual, the memberships was generous with their help.  Last night I purchased an Eagle Fish Easy 350C fishfinder.  I am looking forward to getting out on a pond and giving her a test run.  Thanks again!