It's a bit hard to predict, lots of old machines are available on the used market for a few bucks nowadays, you can have a c64 for something like 20€ as there's been a lot of units which were produced even if it's older than Amiga models. Machines power isn't a criteria either, an A2500 is more expensive than an A3000 and an Apple IIe is worth more than an Amiga 500 (not even talking about Apple IIIs which are even rarer).
It also varies from country to country: purchasing an Archimedes is surely less expensive inside U.K. than anywhere else but Excel or Thomson machines prices would probably sky rocket outside of France, same for Japanese machines which are worth nothing inside the country and can be found everywhere (like NEC's) but are worth gold from an European point of view.
Hardware failures create rarity of models and increase of prices.
Last edited by hitchhikr; 08 September 2009 at 17:05.