Last summer I used two different disposable cameras (Fuji and Kodak) and the results were not too bad, although I wasted many pictures because of low light, or bad focus. If I remember well they are designed for the depth up to 4m, but I took them to 10m with no damage (though I did not take any photos that deep - too low light there).
See some photos from the cameras below. They are all from Corsica. My favorite one is the photo with the colored stones (red, black, green, blue, and spotted) on the yellow rock. It is taken in the Fangu river (with unbelievable clear water). The others are from the sea. The panoramic picture is made of two photos sticked together.
Corse.JPG CorseGaleriaRay.JPG CorseFangu.JPG Corse Galeria.JPG