So here's the crazy thing -- if you pay taxes on the profit you earn, like everything else, your state tends to not care and treats it like any other business.
Though in my state, in excess of 5 vehicles per year they start to care, and prefer you hold a surety bond -- which as of a few months ago, I do for an amount well in excess of the transaction price of the vehicles I typically sell. I also now have a dealer plate, which never goes on anything because some buyers would get weird if they saw one.
