Pricing guides for cars don't always speak with one voice

The letter caught Theodore Tedeschi's attention: Two Saab dealerships were hungry for used cars and willing to buy his 2003 Saab for ''100 percent of its market value."

The Dover resident wanted a new car so he pounced on the deal. But when he went down to Saab City in Framingham in late November to work out the details, he discovered that the dealership's estimate of full market value was nearly $7,000 less than his estimate. In the parlance of car pricing guides, the dealership was talking trade-in value while he was talking retail value.

''When you tell a consumer 'market value,' it's not book value or trade-in value. There's a lot of chaos in the terminology," said Tedeschi, who is now pursuing a lawsuit against the dealership.

There's also a lot of wiggle room in the pricing guides. Even using the same yardstick of trade-in value, Tedeschi and Saab City were still $1,000 to $3,000 apart on estimates of his car's worth because they were relying on different pricing guides.

Consumers today have a lot of information at their fingertips when negotiating with car dealers, excise tax collectors, insurance companies, or banks about the value of a car.

But that doesn't necessarily mean the negotiations will always go smoothly.

Each guidebook is different, and all of them have inherent biases. None of them can take into account all the individual characteristics of a used car, the local market conditions at the time of the sales negotiations, or whether a manufacturer's rebate program on a new minivan depresses the market for a used minivan.

''The books are merely guides," said William DeLuca III, president of the Bill DeLuca Family of Dealerships, which sells Chevrolet, Cadillac, Buick, and Saab autos in Andover and Haverhill. ''I've told customers to give the guides a call and see if they'll buy their car, to make my point. The guides always trail the market and the market is changing all the time."

Mark Perleberg, lead automotive expert at NADAGuides.com, one of the nation's major pricing guides, said a lot of vehicle pricing boils down to supply and demand and negotiating skills.

''If you're a lousy poker player, it doesn't matter what book you read," he said.

The guidebooks all have their target audiences. The Kelley Blue Book is the undisputed leader, providing 35 million pricing reports each month to dealers, consumers, and financial institutions.

Kelley offers three types of vehicle prices: suggested retail value, which is basically a dealer's asking price; private party value, what a buyer can expect to pay when purchasing a used car from another consumer; and trade-in value, an estimate of what a dealer should pay for a used car.

Edmunds is a Kelley clone, offering the same pricing information and in much the same manner. One difference is that Edmunds adjusts a used car's value not just on mileage and vehicle extras, but also on color.

Neither Kelley nor Edmunds charges for pricing estimates. Instead, they sell advertising on their websites, which has drawn criticism from a lesser-known rival, Galves Auto Price List.

Galves, on its website, charges that Edmunds is more in the advertising and marketing business than the car business. It also says the large gap between trade-in and retail values on Kelley is a way for the industry giant to curry favor with auto dealers.

The National Automobile Dealers Association issues pricing guides that are targeted primarily at auto dealers, government agencies, and insurance companies. It offers an average retail and an average trade-in price, both of which need to be adjusted upward or downward, depending on the car's condition and the local market situation.

Galves is not well known among consumers, but it has a strong following among auto dealers, particularly in the Northeast.

Unlike the other three guides, Galves charges for its information and provides only a trade-in price for a ''clean car." Competitors say its prices are often on the low side, an attempt to gain favor with its dealer customer base.

Danny Galves, editor and co-owner of the Galves guidebook, scoffs at the criticism. ''We are probably the most realistic book in the country," he said.

Tedeschi knew very little about the world of guidebooks when he received a letter from Saab City and Charles River Saab saying they were holding a special two-day event where Tedeschi could trade in his 2003 Saab 9-3 for a new 2004 or 2005 model.

The letter said the dealerships would buy his car ''for 100 percent of its market value" so he could obtain a new vehicle ''with little or no out-of-pocket expense." Tedeschi said he would have thrown the letter in the trash if it had said the dealerships would only be offering trade-in value.

At the time, Tedeschi checked out his car on Kelley and discovered its retail value was $21,830 and its trade-in value $16,000. In both instances, he rated his car's condition excellent, which Kelley said applies to less than 5 percent of used cars.

Saab City, relying on the Galves guidebook, offered Tedeschi a $15,000 trade-in price and the dealership's lawyer said later in a letter to Tedeschi that the appropriate Galves price for his vehicle was actually under $13,000.

''In essence, all these Kelley Blue Book quotes for retail value, trade-in value, and private party market value are merely generalities, which may or may not have any applicability to any one particular car or any specific market situation," wrote E. Peter Mullane, the lawyer representing Saab City.

Needless to say, Tedeschi left Saab City in a huff. He subsequently traded in his car at Shaw Saab in Hingham and bought a new vehicle. He received $16,000 for his trade-in.

Bruce Mohl can be reached at mohl@globe.com.