Here in NC, it is perfectly legal and standard practice to take a plate off of one of your cars and put it on the car you are buying out of state. Believe me, I've checked, and done it. You are also covered by your existing insurance (again, I checked with my agent). For the trip home, if you get pulled over (highly unlikely) you've got a legal plate (I also have the registration with me), for a car in your name (it does match your license I hope
), and a bill-of-sale, etc. from the seller. YMMV...