A mobile coupon for the free bottle will be available in the app on August 20. To redeem it, simply show it to the cashier upon check out at participating 7-Eleven locations.
The app is available for both iOS (Apple) and Android mobile devices.
Lemon Daze is a 7-Eleven-exclusive, limited-time Snapple drink that's available in three flavors: Lemonade, Pink Lemonade, and Mango Lemonade. It's normally priced at $1.49 per bottle with a special offer where you can get two for $2.22 through September 5.
In other National Lemonade Day deals, Hot Dog on a Stick will be offering $1 regular-size fresh lemonades from 4pm to 8pm on Tuesday, August 20 (limit one per person). Lemonade flavors include cherry, lime, lite, and blueberry.