I rarely buy new cars. But, I did a few years ago.

There was a logo of the selling company affixed to the back bumper.
After I negotiated a best price, I told the salesperson that, once I owned the car, I would require five hundred dollar fee per year off that price, to be paid in advance for three years advertising charge if their company logo stayed on. I added that, if they could remove it without damaging the finish, I would reverse those charges.