so far, i have a 750$ offer on my SNES-p (he offered 10k, i said 500$, he said 750$), and a 1000$ offer for an n64-p. (though if i do that i will sell it to him for parts cost [best friend])
so, really, its whatever people want to pay. people who have some nostalgia for the system will pay a fluxton, others wont. supply and demand plays a roll too, but not as much in these circles.
also, i will be making a genesis 2 portable with my prize from the donation drive and selling it for the forums (every dollar above parts cost goes to MR), so hopefully that will sell slighty higher than average (though i doubt it)