Think of the rationale if you were Priceline. There is inventory available at the bid level and location but the customer has used up her bid for the day and is close to the lowest threshold. If she waits the "required" 24 hours, the bidder will probably go for a small increase or not wait and choose another travel agency, such as Hotwire. So you give her a "a take it now" offer that assures a sizeable overbid and encourages business for Priceline without the competition being involved. It's a win-win for Priceline if she takes it and it appears to be a deal to the customer as well. Since you (Priceline) make the rules you take advantage of the situation. Of course, if the customer chooses to do a free rebid (or wait) she will get the same accommodations for less. If Priceline ever offered a free new bid at $5 or less over the currently rejected bid I would think they've become a public interest group. The fact is that they probably would like a margin of at least 20% (including fee) and it is reflected in the size of the counteroffer. If the first bid is accepted, it is at least over the minimum acceptable level, not necessarily an overbid but quite likely. Nonetheless, you've bid at a level that you find acceptable, so that is fair enough.