The principal advantage of buying used is, of course, that you avoid the rapid depreciation most new cars undergo. For example, the Kelley Blue Book, an authority on used car prices, lists at $12,310 a 2000 Ford Taurus that cost $17,790 when new. Taxes and insurance will also be lower. The big disadvantage is that you're taking a chance: The car is unlikely to be perfect, and it can be dif?cult to determine what misfortune may lurk beneath the surface. Doing a little preliminary work and using a few easily accessible resources can help ensure that you get a good deal on a good car.

Before looking at actual vehicles, narrow the field—decide what you are looking for. Consider practicalities such as how you'll use the car (commuting, ski trips, hauling your extended family). Car buying isn't completely logical, so also consider how much panache a car must have for your psychic satisfaction. When you've chosen a range of models, be flexible and leave room for unexpected possibilities that may turn up once you're out there looking.

You can get an idea of prices by consulting price guides such as the Kelley Blue Book, either at a library or online. These guides advise but don't dictate. Prices vary by season and region; try the newspapers for an idea of local prices. Sources for used cars include new car dealers, used car lots, private parties, rental companies such as Hertz, and buying services. In each case it's safest to assume that the only person looking out for your own best interest is you.

The Federal Trade Commission (FTC) requires that dealers post a Buyer's Guide label on used cars. It tells whether there is a warranty and, if so, what's covered. And it offers two excellent suggestions: "Spoken promises are difficult to enforce. Ask the dealer to put all promises in writing," and "Ask the dealer if you may have this vehicle inspected by your mechanic either on or off the lot." Think of these as the two commandments.

R E S O U R C E S Federal Trade Commission: www.ftc.gov. California Bureau of Automotive Repair: smogcheck.ca.gov. Consumer Reports magazine annual car issue (April) The Kelley Blue Book: www.kbb.com. National Highway Traffic Safety Administration hotline (for recall information): (800) 424-9393; www.nhtsa.dot.gov. iMotors buying service: aaa.com. AAA Car Care Plus facilities and diagnostic clinics: (800) 652-1158; aaa.com.

The FTC and the California Bureau of Automotive Repair Web sites offer lots of information. Consumer Reports's annual car issue (April) includes picks and pans for used cars, and CR is merciless. (Example: "The Sportage delivers just about the nastiest ride of any passenger vehicle made today. . . . You're also treated to grating road, wind, and engine noise.") If you haven't the time to search out the precise make and model you want, there are online services to help. AAA has joined with one, iMotors, that offers AAA members a special benefit.

When you test-drive a prospect, be sure to use all the accessories. Turn the heater on. Run the wipers. Check all the lights. Toot the horn. Inspect the car yourself for all the usual trouble clues—puddles beneath, wear on the gas pedal, cracked glass, uneven tire wear, loose steering, brakes that pull, and smoky exhaust prominent among them. A test drive and your own nonprofessional inspection will give you an idea of how the car drives and whether there's anything really obvious amiss. But that's not enough. Take the car to a trusted technician for a thorough inspection. AAA can inspect cars at one of its diagnostic clinics or Car Care Plus facilities.

Even though the car has been inspected, unforeseen problems requiring repair soon may arise. Keep this in mind as you negotiate price, and leave yourself some reserve cash.