Yes. In fact I don't think you can book in advance, it's just a normal bus service that happens to cover quite a long distance (and has nicer buses).(Original post by mikeyz54)
Sorry to bring up this thread again, but can a ticket for the x59 be bought on the day? (I'm going from Edinburgh airport to St Andrews and back)
Edit: You just buy the ticket from the driver when you get on the bus. Ask for a return to St Andrews.