What does "all-you-can-something" mean?
"All-you-can-eat," also known by its acronym "AYCE," is another term for buffet. When you enter an AYCE restaurant, you pay a set price and are able to eat as much as you want. In this song, Ed Sheeran is saying that he is thrifty because he goes to buffets, where the emphasis is on quantity over quality. Ex: A: I'm feeling really hungry. B: Should we go to an all-you-can-eat sushi place? Ex: Let's do AYCE wings on Saturday.