I use auctionsniper.com and I've never been charged more than .25c. I almost never lose an auction
. I wanted to warn people though, eBay has caught on to these sites and, I don't know about for other sites, but for my site there is a trick to using it. eBay no longer allows me to "snipe" if I've never placed a bid on the item at all. So that means, in order to "snipe" I place a bid on the item and then setup my snipe. It doesn't matter if my bid is only the next amount up and it is immediately outbid, and if no one else bids you won't bid again.