I'm looking to acquire a fish finder but I need to adhere to a pretty tight budget so it seems my choices are limited. Here is what I am looking for in a fish finder and I'd like to hear what people think is the best value for features, durability and customer service.

I need to stay under $100.
I want it to be able to be easily moved between a canoe and a kayak assuming I can make the appropriate mounting system.
I want a nice readable display that doesn't disappear in bright conditions. I am not crazy about pictures of little fishies on the screen.
It does not need to be able to handle water deeper than about 200 feet usually much less.

So far I have found the Garmin Echo 100, Hummingbird Pirhanamax 153 and Lowrance X4. There may be others and I am still looking and open to suggestions.

Any help would be appreciated.