The Sandwich Delivery Guy is a man who delivers sandwiches.
When Lisa was babysitting Bart, Bart ordered a sub "swimming in vinegar". The man brought it to the house with help from others since it was huge and told Lisa it costs 225$ and tip. He is thrown to the living room by Krusty when he opens the door. Lisa then shouted at him and everyone else Bart had called and told them they weren't wanted.