[you,I] fly [you,I] buy:
commonly heard just prior to a snack bar run: "You fly, I buy" meaning, "If you’ll bundle up and fight your way through this freakin’ blizzard to the snack bar to bring me a cup of hot coffee with cream and two sugars, I’ll buy you one, too." Alternative expression, "You buy, I fly" (commonly used under more moderate weather conditions).
(in Misawaese)

via USAFSS Misawa Family.