Since there isn’t a Festival Center this year, I asked a cast member where to get the AP magnets. They are set up in the hallway behind Club Cool. Just bring your ID and annual pass.
Last year they had buttons for Food and Wine. We got a large button at the Festival center (there were multiple styles over the course of the festival--this was the one when we went over Columbus Day Weekend), and then the 8 new food booths in the Future World Area had small AP buttons if you bought food/drink there. I wish the small buttons had the name of the booth though...no idea which was which!
Seems to be different each year. We have gotten small cutting boards, prints & glasses. We didn't go last year, but wouldn't have stopped to get a button - we're not collectors.