Quoted from Hoteldrummer:

Things including pinball machines are worth what someone is willing to pay. "This rookie card is worth a million ka zillion dollars!" Well what are the offers coming in? Well only a hundred bucks but its worth a million ka zillion because the Becket said so! Soooo......its really worth a hundred bucks. Same here, sellers can list a game for a million ka zillion and if someone pays them that, it was worth a million ka zillion. If not, it will be worth whatever the highest offer is. Personally I hate this crazy shit but I'm not gunna lie and say if I had something I knew would bring in a big crazy offer I wouldn't just because I don't want to offend anyone, I would go after as much as I could and the offers would reveal the ultimate value and worth. Its the buyers that are driving everything up, not the sellers