I'm interested in picking up a copy of Photoshop, but I can't afford the latest version at retail. So I was thinking about looking for a copy of an older version (like 5 or 5.5). I would be using it more as a hobbyist than anything else, so the newest features wouldn't really be an issue. But I'd like to have the option of upgrading in the future, especially if I start using OS X, so I was wondering what Adobe's policy was. Can 5 be upgraded to 7 or later? I checked out Adobe's site, but what I saw was rather vague--seemed to imply that any earlier version of the same platform and region could be upgraded for the same price.
Anyway, what would be the best way to go about finding an older copy? I checked on Ebay, and saw that getting an unregistered copy might be an issue. How do registration transfers work--or do they at all? Might there be any cheap sources of new copies of these older versions (from retailers, say) that were left over when the new versions came out?
Thanks.