Rental cars are almost a perfect product for Priceline. They really are as close to a "commodity" in travel as you'll find. A midsize car from any of the providers (PL uses Hertz, Avis, National, Thrifty, and Alamo I think) is basically as good as a midsize car from any of the other providers (sure you can debate Grand Am versus Contour versus Stratus, but they're all still fine midsize cars I think everyone can agree to).

If you look at some of the winning bids on the PL board, there are some great deals. I've used it three times myself, getting an SUV for $25/day twice and $30/day just last weekend. You might be able to match those on a weekly rental, but not for only a few days.

There are also some unbelievable deals in Florida, mid-size cars for $10/day is a pretty good deal I'd venture to say!

My personal strategy when bidding for rental cars on PL is to find the cheapest full size from a major, then bid roughly the same price for a better car, luxury, SUV, premium in that order (and a convertible if appropriate for the location and time of year). If I don't get it, I just go with the full size through regular means.