I bought a used car from a dealership six states away. The price was so much better than anything I could find in Colorado that it was cheaper to fly out there and drive the car home and still end up with a couple thousand bucks saved over what the same car would have cost locally. At the time of sale the dealership collected the 2.9% CO state sales tax, which they remitted directly to the JeffCo DMV. That was the only tax I paid at the time of sale. I then had to get an emissions test and VIN verification here before going to the DMV with the dealership paperwork to register it. The check I had to write to JeffCo at the registration appointment was f'n brutal. They collected all the remaining county/city/bullshit sales taxes (another ~4.6% on top of the 2.9% the out of state dealership had already collected) in addition to the normal annual registration and title/tag/whatever fees. Man I walked out of that DMV shaking I was so pissed. But from a paperwork/process standpoint it was pretty simple.