I use Priceline alot for hotels. For San Diego, We can get a $150-200 room for about $50/night. Since these trips are discretionary, we go when we get an inexpensive room at a decent hotel. (usually Sunday nites on non holiday weekends). Why pay more for an inferior room at Motel 6 when we get the right hotel, we get free breakfast out of it too! ^

I have used PL twice for car rentals. When my assortment of coupons, discounts, etc. don't work well, I may use PL. Usually I may use PL when my trip includes one or two non weekend days and less than 5 days. (say Sun to Wed).

For air, I used them in early 2001 when PL had a $50 off coupon for air bids. I bought two tickets (LAX-SFO & LAX-PHX) for $100 all in total. I took a $600 bump on the LAX-PHX and used that for 4 more tickets which earned loads of miles because of my knowledge gained on FT. Loads more bumps from the later tickets also resulted which I used for my sub $500 SIN trips in 2002. All said & done, the air don't make sense unless it is last minute and PL comes out ALOT cheaper. Otherwise, using their bidding for air don't make sense to me.