Road Block: You’re interested in buying a used car but have no idea what to look for.

Best Route: There are two. You need to verify the condition of the vehicle, and you need to figure out what it’s worth, says consumer advocate Remar Sutton, president of the Consumer Task Force for Automotive Issues (www.autoissues.org): “You can’t judge the car by how nice it looks or what the seller tells you.” Instead, have an independent mechanic give the car a complete inspection. In some cities, mechanics offer a service in which they go to the dealership and check out the car. But in most cases you’ll need to take the car to a mechanic. “Tell the dealer you want to leave your car with him and drive his vehicle to your mechanic,” says Sutton. “If he gives you any trouble, just walk away and buy a car from somebody else.” Expect to pay $80 to $140 for the inspection, and ask the mechanic to run a full diagnostic on the vehicle and let you know how much it will cost to make any necessary repairs and get the car in good driving order. Then you can ask the seller to make those repairs or to knock their cost off the selling price.

Speaking of price, forget about the dealer’s asking price. As with a new car, you want to negotiate up from the wholesale price, not down from the sticker price. But there’s no invoice for a used car; the best way to determine the wholesale number is by contacting your loan officer at a local bank or credit union, providing all the details about the vehicle (make, model, year, trim line, accessories, mileage), and asking for the vehicle’s “black book value.” That’s the amount the bank lends to dealers to buy that car (yes, dealers take out car loans, too), and it’s the closest thing you can get to wholesale value for the vehicle. Consumer Reports also has used-car price reports available for $12 (www.consumerreports.org). “You want to negotiate a price that’s as close to the loan value as possible,” says Sutton.