I wouldn't say what something sells for on Ebay indicates it's "fair market value". I've bought and sold lots of stuff for both far more and far less than it's "fair market value." I recently bought a rare book on Ebay that I have been after for more than a year. It usually sells on Ebay for $35-$40us on Ebay. I paid $17 for it with no sniping--bid a day and a half before the auction end and was delightfully surprised to see an item won email in my inbox. The seller told me he had paid $90 for it on Ebay the year before and was surprised it sold for so little. I recently sold one of my guitars that was appraised at around $1000 for $400. I wasn't that disappointed because I had followed some auctions of this guitar and the bids never went much over $400 in spite of the appraised value and most of the sellers had set their reserve prices and expectations too high and none of them sold. I got a realistic market value for my guitar and since this was about 4 times what I paid for it and I wasn't playing it all, I was satisfied with what I got.
I've seen a lot of high end Amiga gear listed at high prices and relisted several times with no sale--lots of seller fees for Ebay and nothing for the seller. I've also seen items listed for 99 cents go for astounding prices. There is an element of chance and just timing things right that makes things happen on Ebay. 2 days ago I bought a DKB megachip 2000 for $28 buy it now--shipping included. One just sold for $51 this afternoon--shipping not included. I've seen them sell for well over $100. I would say that the $51 is closer to the fair market value and I was just lucky enough to be online when one came up at a below market value. I don't think it would have lasted more than an hour at that price. Sometimes there are the right fools with the right amount of money to spend when you list things. It can favor both buyer and seller. A few months ago, there was an A1200 with a buy it now price of $37 and a minimum bid of 9.99. I quickly clicked on the buy it now button but someone had already put in the minimum bid. I just laughed, you idiot, you just made the seller at least a hundred dollars.
Point being that just because something sells for one price one day, doesn't mean it will sell for the same price the next day. There are always those who will try to manipulate the price and perceived value of an item to their advantage one way or the other and there will always be sellers with high expectations and just due to chance and human nature, they won't always be dissapointed. I was discussing this recently with and acquaintance who has worked as an Auctioneer and he said that live auctions weren't that different from Ebay in this regard and that some days things went real high and that some days there were bargains to be had.
