Thrillist.com: Included Wayback Burgers and its deal for National Cheeseburger Day in a roundup of free and discounted food on September 6.

Wayback Burgers
The deal: 
There’s a buy-one-get-one-free deal on the Classic Burger for National Cheeseburger Day. Order through the Wayback app.
When: September 18

Source: https://www.thrillist.com/news/nation/free-food-deals