Is it worth the price depends on the buyer really. Not too long ago you could get one under $50, who knows what they will cost in 10 years. 8MB of RAM is enough for most tasks on an 030, 32MB is what I have in both of mine and that's enough for all I do with them (massive amount compared to what they shipped with).

IIfx and 840AV are going to be the most collectable desktops so finding either one at a good price is a good idea.