Snacks have to be $4 or less and considered a single serving to use a snack credit...there are still some restrictions with the above in mind...no single slice pizza,no kids meals, and no funnel cakes in Epcot are just a few that come to mind. Disney usually has the items marked with a special symbol on the menu...if in doubt (or something does not have this symbol beside it and you want it) just ask the CM, they are wonderful at helping you decide. Have fun!