I'm sort of waiting to buy small stuff - OOT bags, menu cards, etc - until the end when I know how many people are coming. I'm spending $$ now on the deposits, dress, photographer, etc. I'm also saving the balance I owe the big vendors so I have it when the time comes. For example, before I booked the photog and put down a deposit I made sure I had the full amount.
I'm a bad budgeter so this way I don't get in over my head.