From the Coupons.com Deal Hunter:
Nothing tastes better than free food. Download the new Chick-fil-A One app via iOS or Android and score a free original, spicy, or grilled chicken sandwich. On the app menu screen, select a sandwich of your choice under the “available treats” window and it will be added to your account. This coupon is valid as a mobile order or for use in your local Chick-fil-A.
Deal Details: Free Chick-fil-A chicken sandwich when you download the new mobile app. Must be redeemed by June 30, 2016. Valid at participating Chick-fil-A restaurants only. This offer is limited to one per app account.
Deal Dates: Valid through 6/11/2016