Many consumers look on Craigslist.com.  You can find just about anything you might want, and a few things you really would not want to take home with you.  One of the busiest areas on craigslist.com is the auto and truck section.  I wouldn't want to guess the number of entry's that are made everyday, but it is staggering.

There are 3 auto sections.  all, dealer and private party.  According to Arizona statute 28-4301-35 a "used motor vehicle dealer" is defined as a person, other than a new motor vehicle dealer, who buys, sells, auctions, exchanges or offers or attempted to negotiate a sale or exchange of an interest in, or who is engaged in the selling, four or more used motor vehicle dealers in a contiguous twelve month period.  Used motor vehicle dealer does not include a wholesale motor vehicle auction dealer, or a public consignment auction dealer."

If you look at private party listings, copy a phone number from an ad and put it in the search bar.  I have seen as many as 15 cars listed with the same phone number at the same time.  If you apply the statute listed above to the person offering these cars, that person is considered to be a dealer by the State of Arizona.

If you want to take a chance, that is ok.  The car you are looking at may be a great one, but it also could be ready to fall apart.  Also I would make sure that I take someone else with me to help examine the car and make sure there are no serious issues.  Some of the newer transmissions can be $2000-3000 or more to rebuild.  The better thing to do would be to visit a used car dealership,at least you then know exactly where to go back to if you have a problem.  Also there is no such thing as an "as-is" sale of a car in Arizona, so if there are problems, you can work something out with the seller to get the car repaired or get your money refunded.

USED CAR AS-IS STICKERS

Are you aware that every used car for sale at a dealership is required to have a Federal As-Is warranty sticker since this was required since 1985. Non compliance can be subject to up to a $10,000 civil fine for each car that is displayed without a sticker.

I see many lots that don't display the federal sticker.  When asked why not, they say "Nobody ever checks on this".  Not displaying these could be terribly expensive if you get caught.

In Arizona used cars are sold with a 15 day, 500 mile implied warranty. This means that the car will run and drive in for this length of time. This doesn't require that the a/c blows cold or the power windows work.    If you are not able to drive it safely  for normal everyday use, the dealer is required to fix it, take the car back and cancel the deal or come to a solution that is acceptable to both parties.  Because of this in Arizona it is against the law for a dealer to sell a car "As-Is".  It is ok to sell a car that has mechanical problems if the problems are clearly marked on the purchase order and the buyer acknowledges that he is aware of these problems.
The following link describes the law that has been in effect for almost 30 years.

  http://www.ftc.gov/bcp/guides/usedcar-comply.shtm