If you need to, a lot of breeders will hold a snake if you put a deposit on them and talk with the breeder, but there are sometimes when you'll be stuck paying the extra for shipping (if they're not very local), and I assume most expo breeders are trying to go home without snakes. It all depends on the breeder.

That may be a good alternative, since I know I'd be a little worried about leaving a brand new snake by itself for a week, just because I want to know that its settling in alright and has no issues.