My family and I have a trip planned for the end of August. We will be staying for 7 nights, but will be arriving early on the day we get there and leaving late when we go home, so we will have 8 days in the parks. I know that I can get tickets cheaper from one of the online sellers (DW Tickets or Maple Leaf) but they do not seem to have an 8 day option. Does anyone know if I can buy a 7 day park hopper ticket from one of the online places, and then add an additional day when I get to WDW? Also, would I just be paying the difference between a 7 and 8 day ticket?