THE MARKUP PROBLEM One thing consumers may not realize when applying for an auto loan through many dealers is that it’s often the dealers, not the company providing the loan, that ultimately decide how much you’ll pay. A bank quotes a wholesale rate to the dealer, and then the dealer is free to mark it up by as much as 3 percentage points. The dealer’s ultimate profit on any deal depends in part on how much it marks up this rate.

Image Consumer and military organizations wanted auto dealers covered in the financial overhaul bill. Credit... Steve Dykes for The New York Times

That spread used to be higher, before a number of lawsuits using data from as recently as 2004 revealed that blacks and Hispanics were paying more for their loans, even when they had the same credit scores as whites. And in case you didn’t believe that everyone’s a little bit racist sometimes, lawyers in one lawsuit determined that minority-owned dealers had the biggest markups, according to Stuart Rossman of the National Consumer Law Center in Boston, who was co-counsel on the cases.

It’s not clear what the numbers are today, but remember that on many parts of the Internet, no one knows you’re black. So get preapproved for an auto loan via a bank’s or credit union’s online application process before going to a dealer to discuss financing. Then, no matter what your skin color, ask the dealer to beat that rate.

THE ADD-ON PROBLEM If you’ve gotten a good price on the car and arrived with cash or a loan from someplace else, dealers will try to find some other way to make money off you. In fact, lawyers for the finance companies that supply dealer loans promised Mr. Rossman as much when he was in the middle of suing them. “I would see them at legal conferences, and they would tell me that if we stopped them from doing what they were doing, they would just move their profit margins someplace else,” he said.

And so the dealers try to sell you window etchings and service contracts, or disability and other insurance. Or, they try to force you to buy these things by implying that the add-ons are a condition of getting a loan or getting a good rate on one.

Mr. Bailey of the dealers association says that this is illegal, but some dealers do it anyway. The Oregon Justice Department has taken action twice in the last two years against dealers like this. In August 2008, it reached a $100,000 settlement agreement with Salem Nissan in Salem, Ore., after finding that the dealership had added all sorts of products to almost all its contracts without the buyers knowing they didn’t have to buy them. As is standard in these sorts of agreements, the dealership admitted no violation of the law.

Most of these products are of questionable value or available in better, cheaper versions elsewhere. Keep a careful eye on your paperwork to see if they’ve ended up on your bill.