Yes, the original cells can be quite expensive (the old Courvoisier Galleries ones, and such), even if they're not in the greatest condition.
I remember seeing one on there a few years ago from Snow White (I think it was one of the old hag holding the poison apple) for $19,000 USD.
I own 5 pieces of Disney art from that site.
2 photostat model sheets of Donald Duck, one of Pluto, one from Pinocchio, and a small original animation drawing of Donald Duck from a cartoon from '82.
Unfortunately, I couldn't afford the $19,000 hag.