The deal can be found in the "offers" tab of the Popeyes website and mobile app.
For the promotion, you can choose from the Classic Chicken Sandwich, Spicy Chicken Sandwich, and Ghost Pepper Chicken Sandwich. All three include a crispy-fried buttermilk-battered chicken breast filet and barrel-cured pickles served on a buttered and toasted brioche bun but differ in the included sauce. The Classic comes with mayo, the Spicy comes with spicy mayo, and the Ghost Pepper comes with Ghost Pepper sauce.
The deal is specifically not available in Alaska, Hawaii, the US Virgin Islands, and Puerto Rico. It may cost more in some areas (it's $5 here in Los Angeles). The Chicken Sandwich is normally $5.99 here.
Photo via Popeyes.