Priceline is the bomb for hotels and car rentals. Here are some of my recent coups:
Three star hotel in the heart of downtown Chicago, a couple blocks from the Water Tower: $50/night
Three star hotel in downtown Pittsburgh, across from Mellon arena: $50/night
Three star hotel in downtown Austin with full in-room kitchen: $50/night
Notice a trend? Bid $50.
It's much riskier for airline tickets because you don't know if you'll get a flight that leaves at 7:00AM or 10:00PM. The window is much too wide to make it a viable form of transportation, in my opinion. I get my airline tickets through Hotwire and all other accomodations on Priceline.