Cups are relatively expensive to craft, and there's no way to automate limestone production from what I understand.

Why not return the user an empty cup after drinking? Or at least make them much cheaper to craft? (Have the recipe give you like, 3 empty boba cups instead of just one, the same amount of vanilla bottles you'd get for 3 glass blocks)

You can technically automate limestone with a quarry, it'll just be slow, and the recipe only uses 1 slab, but I'll increase the amount of cups per recipe to 3. I didn't have the drinks give you the cups back because I get annoyed when I get bowls in my inventory after eating soup, but I'll make the drinks give you an empty cup back by default and make a config to disable that.

Added config option to give empty cups from drinks (enabled by default)