last time I sold thru an auction house the auctioneer charged the Seller (me) 22.5%commission on the final price, and also charged the Buyer (my customer) 17.5% commission on the final price. (so of course he would have lowered his top bid to accommodate that, effectivly I paid the 22.5 and the 17.5 % commissions.......

give me ebay any day