Car manufacturers with their own financing departments may offer lower interest rates on loans and leases than rates that are available from outside credit sources. To ensure goodwill, some pay the security deposit and first monthly payment when you lease the next car from them after a previous lease contract with them expires. Others offer perks such as free maintenance, auto club and towing services, emergency hotlines, stolen-vehicle tracking, and other goodies. Generally speaking, the more expensive the vehicle, the greater the perks offered by the manufacturer.

Auto manufacturers run frequent promotions that offer you the choice between a rebate or a low-interest deal. Ask your accountant or a friend who's good with numbers to work out which alternative would be the most profitable arrangement for you.

If you go for the rebate, ask the dealer to base the sales or lease contract on the price of the vehicle after the rebate has been deducted, instead of writing the contract for the original price and mailing you the rebate later on. Doing this enables you to avoid paying higher taxes, interest, registration fees, and perhaps insurance, on the pre-rebate price of the vehicle, which may be a couple of thousand dollars more than the vehicle actually costs you.