I have a Canon A75 with Canon waterproof housing for sale. (I think Canon lists the box as waterproof down to 130 feet.) It includes a 1 gb Lexar professional card and a home-made foam box to protect the housing when traveling. I used it for 3 snorkel trips (2 to Bonaire, 1 to Hawaii) and got some very nice pix. I also used it topside when I did not want to schlep my DSLR with me.
I have just listed it locally for $175.
I have moved up to a Canon G9 system with external strobe. It was quite a bit more expensive ($2000 for the camera, 2 strobes, arms, trays, external lenses, focusing light, Canon housing and Ikelight housing and more). I bought it used and couldn't be happier (unless someone gave me the money to upgrade to a housing and port for my Nikon D80 for UW photography.)
If you are interested in the Canon A75 camera outfit, please contact me first about the kinds of pix you like to take, your prior experience. You might not be able to do what you want for an investment of $150.
Laura