To get a good deal on wheels, you need to play with the numbers—and play dealers off one another. The following are some ideas on how to get a good deal on purchasing an automobile from the article “Cars” in Money magazine (May 2012, pp. 70-1):
Avoid the hard sell by deciding on the model and options before you step onto the car lot. Review websites, read reviews, and ask your friends for recommendations. Visit dealers and test drive before you tell salesmen you are ready to buy.
Shop your old car to the dealer. Nowadays, dealerships are hungry for high-profit used cars and may give you top dollar. First, take your car to CarMax. They’ll give you an offer good for 7 days. Then ask your dealer to beat it.
Compare total cost of ownership. Consider  the purchase price,  depreciation over the time you expect to own the car (get an estimate at Intellichoice.com),  insurance premiums,  fuel costs, and  maintenance and repairs.
Negotiate from home. You have an advantage when you avoid negotiating face-to-face with a salesman on his territory. Truecar.com and Carwoo.com are two websites where you can anonymously negotiate with multiple dealers at once to quickly get the best price. You can also call a dealership to negotiate about a specific car in their inventory.
Check the history of the car before you buy it. Use a free service like AutoCheck to see if the car has been in an accident and confirm the reported mileage.
Know your car loan rate. Beforehand, know your best options from credit unions or local banks. Then see if the dealership can make a better offer.
Extended warranties are not a deal. Regular warranties usually cover the most expensive and critical car components. If you change your mind, you can buy the extended version any time before the factory warranty expires. Learn more about extended warranties.