Home Slickdeals Burger King Is Giving Away Free Burgers for National Cheeseburger Day 9/18... Slickdeals Burger King Is Giving Away Free Burgers for National Cheeseburger Day 9/18 & 9/19 with $1 purchase. By ARCOM - 18 September 2023 20 0 SHARE Facebook Twitter Go to the deal page: Burger King Is Giving Away Free Burgers for National Cheeseburger Day 9/18 & 9/19 with $1 purchase.