US-centric: No car, new or used, has just one price—there's a "published invoice" price, an MSRP listing, the "Blue Book value," and many more to weigh when haggling with a dealer or private party. PriceHub, a price-tracking web site for new and used cars, serves up real and recent transaction prices submitted by users. Enter your car's make and model into the search and see what cars like it went for. It seems, at a glance, like cars suited for auto enthusiasts (Porsches, BMWs and the like) get the most listings, but I was able to see what my Nissan Sentra, with less mileage, is going for—and now I'm suitably depressed. For more automotive backup, see how to buy a car without getting screwed and learn how to protect yourself from used car scams.