Hosed by DMV

Just got back from DMV and even though I got over on them for surely a couple grand the last round they just settled the score... I bought my Evo fro a private seller and everyone knows you have to pay taxes, so I did the honest thing for once and put down the price I paid... Yeah thats what I did.... Anyway I paid sales tax of like $550 bucks for my Evo that cost me $6,000.00! She asked if I wanted to pay my registration while I was there and I was like sure why not, she said total comes out to $639.00... I was like WTF... Score is tied DMV Vs. Nick 1-1... Still gotta get a SMOG check though and those usually never go well haha.