Priceline

Priceline.com: The amazing travel service where you can now choose your exact flights and times for incredible travel savings or Name Your Own Price and save even more! All it takes is a little flexibility with your travel plans.
If you can fly any time of day, agree to fly on any major airline, stay in any name-brand hotel or rent from any of the top 5 U.S. rental car agencies - you can save a lot of money with priceline!.
More at:http://www.priceline.com/