You either must know a licensed car dealer or someone you trust in the automotive industry. But most people wouldn’t want to go through this much trouble to buy a single vehicle. All the auctions listed on Classics on Autotrader are open to the public and do not require buyers to have a dealer license. If you still insist on buying a car from a private dealer auction, your best bet is to find a car broker who focuses on representing clients, like you, to buy a vehicle at a dealer car auction.