C-64c, How common?

I'm assuming you mean the different case design - over here (South Australia) they seem to be as common as the old breadbox sort, but I suspect that in numbers they are slightly less than the older designs. I have three of them, and I only wanted the one. As far as I know there are no functional changes, although Commodore had a history of working out ways to make systems cheaper, so there may be a difference internally. I did find one old C64 in a third-party case which looked very much like the C64c, though. Interestingly enough it was made here - I would have picked it up, but I shy away from collecting computers based on the different cases, as there are too many to collect just based on the different systems themselves, and space is limited. Adam.