My bids have never been accepted and they have been reasonable bids. The site is reasonably fast and the service is legit. Customer Reports did a report on them and noted that a good advanced-purchase fare beats them. So the time to use them is when you have less than 14/7 days to go or you cannot stay over on a Sat. night. If you pick a price higher than the adv. purchase fare but well below full-fare you have a really good chance of it being accepted. If you can get a good deal through bestfares.com or lowestfare.com (the TWA thang) or for international consolidators www.tiss.com than you are better off than priceline.com