If folks honestly believe that his is inflating the prices that his cars have sold for, and then uses these 'shill' prices in advertising, a report should be filed with the FTC:
http://www.ftc.gov/ftc/consumer.htm
As a merchant, he is under specific rules promulgated under the UCC. While there is no law against his asking a "sky is the limit" price, he cannot fraudulently state that he sold another car at that price.