By Emily Lee Free french fries right this way. Last week, Shake Shack announced an exciting new promotion for its New York City customers. If you live in the Big Apple and have received the COVID-19 vaccine, you can score free french fries at Shake Shack. The popular burger joint teamed up with the NYC Mayor's Office to help encourage more people to get vaccinated. As part of the partnership, Shake Shack is offering a free order of regular-sized crinkle-cut fries when you buy a burger or chicken sandwich in-store after you've gotten your shot. You must show a valid vaccine card or Excelsior Pass to get your free order of fries.