OK, I called the DMV and here is the info:
$280 plates, tag, paper registration
$740 sales tax at time of titling 8.3% of my purchase price
$8915 sale Price.
According to this calculation, they tried to charge me about $800 more. They had some "smooth-talking" guy call me today again. I told him I was looking at other cars. Just out of principal, I can deal with slime used car salespeople. Ick.