I will be travelling around the same time and was wondering the same thing. From what I have seen, a number of airlines will allow you to book your flights and if a lower cost appears for your flight from now until then, they will give you credit for a future flight. As mentioned some hotels offer the same advantage or at least the ability to cancel one reservation to make another. I think the big one is park tickets. Look to some of the airline websites for discounts. I have been surprised to find reduced cost park hopper tickets through Alaska Air. I'm sure there must be other companies that offer this as well.