The best way to minimize this kind of problem is, when negotiating the
price on a car, new or used, negotiate

The best way to minimize this kind of problem is, when negotiating the
price on a car, new or used, negotiate only on a total price, in the
terms of the car salesman, the Out The Door price. When you sign a PO
with the maximum amount you are willing to pay, write a note next to the
total saying something to the effect �Total including all taxes and fees�.

This saved me almost $400 on one purchase I made when they tried to add
in a bunch of fees when I came to pick up the plates. (Based on the
experience of a former car salesman, a short interlude during my
misspent youth)