Carfax is a free service that gives you above all the ability to check the history of a used car before you buy. This ensures that you can buy the best vehicle with the money you have. The only information that is not in a carfax are names, phone numbers and addresses of previous owners. The only case that a history of Carfax can not be free is if you are buying from a dealer, but a private person. This person may not want to include a free history so you can pay for it Carfax.