I think those Priceline commercials featuring William Shatner are great. But I had never actually used Priceline until today. I needed to rent an SUV for a trip my family and I are planning around Christmas time, so I gave Priceline a try. All the rental prices I looked at elsewhere were astronomical. So just on a whim I entered a much lower figure on the Priceline website...and it was accepted by Avis! It was about half the going rate from the cheapest rental car company. Even with taxes and fees added in, it looks like I saved over $400.
Next time I'm looking for a hotel or car or something, I'll check out Priceline again.