Used cars presented no such obstacles. In fact, there is a boom in used car sales. Used cars and trucks have outsold new vehicles for four consecutive years, and prices and profits on used cars are rising, auto experts say. There is also a generous supply of low-mileage used cars on the market, thanks to new-car lease programs and rental fleets that turn back large numbers of cars. More and more buyers are choosing used cars over new ones because they still cost relatively less and because quality improvements have produced more durable vehicles. A Common History

Used cars also shared a history with the consumer electronics and appliance industry.

Twelve years ago, when Circuit City was opening its first Superstores, consumer electronics was still highly fragmented, with some of the chains named after people like Mad Man Muntz and Crazy Eddie. While they and others may have delivered goods at reasonably low prices, consumers often walked away feeling uneasy. Did they get the best value for the price? Will the company stand behind the product? Will the store still be there if there is a problem?

"This was an industry that ranked from shady to illegal," said Kenneth M. Gassman, Jr., a securities analyst for Davenport & Company in Richmond. "The public perception of it was horrible, just horrible. People had no confidence. That's the way consumer electronics was."

Circuit City's strategy was to allay all those fears, with huge modern stores, a wide selection at each price, knowledgable sales people, affordable financing and warranties for products and service. In essence, they were the same elements that could be applied to the used-car business. To Attract 'the Mainstream'

Just as Circuit City is stocked with goods that would appeal to a vast majority of consumers, Carmax was designed to attract "the 80 percent in the mainstream" of drivers, as Mr. Sharp said. To fulfill that vision, the 500-car lot is filled with vehicles within the $8,000 to $15,000 price range. There are virtually no clunkers and most cars are less than five years old. Circuit City acquires most of them from leasing companies, car-rental agencies and auctions.

Besides a bright showroom and salespeople dressed in polo shirts, slacks and sneakers -- half of whom are women -- the sales techniques are fashioned as the principal weapons against public mistrust.

Each new customer is invited to sit before a computer screen with a sales person and enter the features desired in a car, a particular make, a price range or any combination of factors. The computer produces color pictures of the choices on the screen, with a listing of features, specifications, mileage, price and the location of the car on the lot. The customer can print out sheets for any car listed.