The answer might be: a lot. According to Edmunds.com, the mega-site for all things car-sale-related, they are meant to get shoppers to visit particular dealerships, or direct them to specific, low-selling models – especially as the year winds down in late summer and dealers scramble to make space for new vehicles.

A few points to keep in mind before making a decision on zero-interest financing:

  • According to AutoTrader.com, zero-percent interest is often available only to the top ten percent of shoppers with the very best credit scores and history.
  • These loans are offered almost exclusively on new cars, or for limited models. You might find a much better deal, even carrying modest interest, for a different vehicle.
  • Low interest rates are often tied to shorter-term loans, so you could end up with a considerably higher payment every month.
  • Dealers are less likely to haggle on price when they know that they won’t be making money on the loan – or they may pressure you into expensive add-ons.
  • There is often a choice of cash rebate OR zero-interest loan. Edmunds.com points out that you might be able to save money in the long run by negotiating your best rate with a bank or credit union, and using the rebate to reduce the amount financed.

Experts recommend you take the step of getting preapproved by a bank or credit union before going to the dealership. (US News & World Report Money points out that consumers often find better rates and more-personalized service at a credit union like Sikorsky Credit Union, rather than a commercial bank.) That way, you can compare interest rates and total cost on different vehicles. This also helps reduce the pressure to “make a deal” on the spot. Lastly, check your credit reports ahead of time and be prepared to negotiate your best price BEFORE you talk financing.

Calculate your numbers ahead of time to figure out the best deal.