a1000s in worse condition have gone for quite a bit. that one seems to be in excellent condition.
a $500 buy it now could also indicate that they want the option but they dont want to limit it at all. if someone snapps up an auction with buy it now you wonder if a straight out action could have done even better. maybe they want real bidding and dont really intend for anyone to use the buy it now.
keep in mind it is an auction site, if you want just fixed prices go to amigakit, or software hut or something like that. considering someone stupid simply because they put a high buy it now price is kindof rude. if you want the computer put whatever bid you are willing to pay and hope for the best. with a $99 starting bid you could win it.