We bought our AP's (using the DVC Discount) with Cash at Downtown Disney (room connected with Team Mickey). For us this was easier b/c we wanted to pay cash and not charge it, and b/c we usually stop at Downtown Disney before we hit the hotel.
This is the Disney Dining Experience card. It is available to Annual Pass holders as well as Florida residents and will get you 20% off at many table service restaurants and some counter service restaurants at the Disney Parks and resorts.