You can either preselect or wait to order in person. Even if u preorder, u don't pay until u arrive is my understanding. But we are on the QS dining plan so I don't know that for certain from experience. For us, it showed the $72 total and a button to turn the DDP on or off. I slid it to On and then my total went to zero. So I can't speak to that. But I have been reading about this for months now & I don't believe you must pay in advance.