Another interesting one I've seen: Upside.

It isn't necessarily encouraging to buy a specific product, but rather to buy from specific businesses.

To the consumer: they look at the app and buy gas from participating stores, which typically show as having a 5-10 cent discount on gas. The customer uploads a picture of their receipt to confirm the purchase and amount, and get credited that discount. Theres a monthly purvhase target that unlocks a 1 time discount of 30 cents per gallon, etc.

To the business: they pay a fee to Upside to be a participant. Upside promises to only participate with a certain % of stores in the area. It's likely the business also pays for some of the discounts obtained.

Essentially paying upside is meant to increase sales volume. While a gas station could just dicount their gas, they are paying Upaide to effectively advertise and steer consumers to THAT store. As Upside is national, many custpmers use it, even in unfamiliar areas to choose gas stations.

I say not a specific product, because my understanding is it's extended to other business categories besides gas.

Market manipulation, ultimately. I'm sure in some part they are sellong your location & purchase data as well.