DH and I got a pizza with Mickey & Friends on the box to-go at the Mara at Animal Kingdom Lodge. The bigger pizzas weren't on the menu, but DH saw another guest with one and asked if he could have one as well. Thinking they were less than $15 maybe. This was October '08, so it could have changed since then. For what it's worth, we really liked the pizza!
Hope you have a wonderful time on your trip!