I have an epic housing and a bag style housing. The epic housing is heavy if you are filming from a tube, and murder if the driver doesn't backoff on the turn around. The bag style is better. Both were about $300 for the Cannon GL2 camera. They are less expensive for smaller cameras. The bag style looks like it would be frail but I've used it for dozens of shoots and it's awsome.
http://www.waterproofcases.net/waterproof-camera-cases.html Here is one link there are others depending on the camera you are using. You don't need it to be waterproof beyond 30 feet unless you are going to scuba dive with it....
Good luck..