I bought a new webcam on Ebay last week that I'll be using for my ISS imaging as well as lunar/planetary work. I've been using an old Vesta Pro webcam for many years and see that this one (Philips SPC900NC) has higher resolution, more pixels, and will go up to 90 fps. I won't go that high on the fps (frames per second) though. My hard drive on the observatory computer starts barfing frames at 10 fps, so I never go faster than that. I'll need a faster drive to go higher but 10 fps has always been perfect.
Camera was $40 and the adapter for the scope was another $18. I've been tempted by the Orion Starshoot III, but think this would probably do close enough for a fraction of the cost. Below is an example of some planetary imaging with a cheap webcam. (click for full size)