A pizza delivery franchise run by people who are easily duped into thinking that they delivered the wrong thing, therefore making your dinner free of charge. This can be done over and over again, even when complaining about things you were given for free.
If speaking a staff member who's first language is not English, garlic breads and potato wedges can also be obtained by claiming to have vouchers. The drivers never ask for these.
During quiet periods one can also obtain a free ride home by ordering one of said free pizzas and telling the driver you will tip him if he does you a favour.