When it comes to financing, many of the advertised interest rates from manufacturers look lower than outside banks. "However, the rate can change depending upon the year and model," Lapolla says.

Before settling on a finance deal with a dealer, check for differences in interest rates between various makes and models. Then ask about financing plans at your bank or credit union. You may find that a car that seemed out of your price range is actually a more affordable option.

Dealers often tack on extras such as extended warranties, dealer-installed equipment, paint protection or rust-proofing. "The markup on these is extremely high, so you'll want to negotiate if you decide you want any extras," Shattuck says.