Well, I traded in my car for a credit towards purchase, but in California we don't get to adjust our sales tax. Pretty much what mknox said. I went through a web questionnaire about the car, and they gave me a price. When I said I was interested, they (AutoNation) arranged for somebody to come by the house and inspect the car. At the end of the inspection I signed the papers and gave them the title. My MVPA had the trade in price as a credit.