The concept of a massive discount on a footlong sandwich didn't start in a corporate boardroom. It began in with Stuart Frankel, a Florida franchisee who dropped his weekend footlong prices to $5 simply to drive traffic.

: By 2008, Subway took the deal national during the recession, generating $3.8 billion in sales in just one year.

: Deals often require a specific code like FLBOGO or BOGOFL during checkout on the app or website.

: Within two weeks, his sales jumped from $14,000 to $23,000 weekly.