Burger King is giving away free hamburgers to celebrate the debut of a new sandwich, the Big King XL.<br /><br />Customers can get the free burgers by placing a minimum $3 order from Burger King through Grubhub's app or website.<br /><br />Burger King will add a Big King XL to the order for free. Grubhub is waiving delivery fees during the promotion. <br /><br />The Big King XL, which launched nationwide on Thursday, is Burger King's take on rival McDonald's Big Mac. <br />
