I looked into camera housing for my camera back then. It costs over $500 even on eBay. When I was in Michigan, I was with a diving master who had lots of equipment, but unfortunately there was not much I wanted to take pictures of in the lakes.
Last time while in Egypt, I wanted to rent a camera (forgot how much it cost, maybe $20). Now I don't remember what happened--the camera was malfunctioning or something. I didn't get any photos back.
Now we don't go diving much. Renting the equipment each time probably is the best deal.