A retail brand lets people know it's going to be sending special "surprise discount coupons" via Snapchat. They work like this: You receive the Snap but you don't open it. You go to that store, buy something and then, at the register, you open the Snap with the cashier watching, and you both discover the discount together for the first and only time! It could be 5%, 20%, 90% or even a secret prize! Every Snap is different and you can't open it ahead of time because it only lasts a few seconds!