Carfox is a joke.
If you know enough about cars Craigslist is the way to go. Or if you have a mechanic you trust they will check it out for you pretty cheap.
Simple private sale, seller has no overhead.
Dealer LOTS of over head.
Of course if money isn't an issue, dealer is the easier way to go. Just avoid those little corner car lots. Those guys are worse then scammers on Craigslist!