Most will give you a plastic container

But just in case you don't get that, bring your own pillow case to put him in. is it really hot where you are? If not, then that should be all you need. just keep him in a not too warm/not too cool place for your drive and you'll be good. Not in direct sunlight either.

Most breeders will hang onto the snake and mark it as "sold" and you can pick it up whenever you leave