auctionsniper.com is what I've used... You're first three snipes are free, and then it's like $0.25 per snipe afterwards... You tell them your highest bid, and set it for however long before auction ending (minutes or seconds), and it'll put in the bid for you. Should the bid hit above the highest you'll go before the end of the auction, you'll receive a message about it. I've won a few auctions like that by sniping in the last 5 seconds
