Japanese conbini convenience stores are on literally every corner in Tokyo. Open 24 hours, these stores stock surprisingly decent food and snacks (some locals live on the ramen, onigiri rice balls, and other prepared food available round the clock). They’re decently stocked on beer and liquor, if you need a cheap boost at any hour. Worth stopping by one for their quirky drinks, snack, and candy selection (Crunky, anyone?), or if you need to pick up some toiletries after missing your last train home, maybe use the bathroom. The Lawsons chain also has ticket vending machines, where you can buy concert tickets, etc. but only in Japanese.