What do I do about license plates when buying a car in PA if I'm driving it home to IL?

If you're buying new or used through a dealer, tell them you want to register out of state, and they will give you a temporary plate. If you are buying from an individual, go to the DMV and get a moving permit to take the car home. In either case you will have to have insurance in place before you move it.

It is unlawful to force with out plates and worse to take plates from one more auto. I am assuming they've vainness plates or theirs have been stolen. You ought to move to the dmv or dot for your state and get a transitority plate. A little piece of paper you stick within the window.

I would drive it home, and re register it it your home state. It shouldn't be a problem, unless it won't pass your states emissions requirements, or other needed requirements. Just have proof to show that you just bought it, in case you are stopped along the way.