Kelley Blue Book is the generally accepted authority in the pricing and valuation of cars and offers a feature on its website that provides the appraised value of a 2007 Mercedes S550. Final selling price varies by seller, but most dealers use this valuation in making that determination.
The Kelley Blue Book value of a specific Mercedes S550 depends on a number of factors including mileage, condition and optional features. The value also varies based on whether the vehicle is being traded to a dealership or sold to a private buyer. To find specific selling prices of dealers in a certain area, websites such as autotrader.com connect sellers to potential buyers.