Promotion marketing is possibly the most effective and popular form of reward marketing used today.
An example would be a hairdresser who advertising the eighth haircut is free another example might be a pet shop that advertises buy seven bags of dog food, and the eighth bag is free.
Since few of us require eight haircuts or large bags of dog food now, what the proprietor does is note every time you come and if within a certain period, you reach their benchmark, you get on the next visit the free item, this encourages the customer to come back.
Of course, it is not limited to the same item; it can be, for example, buy nine ink jets, and you get a ream of paper free.
Our point-of-sale system does this very well. To set it up follow the red arrows in the image below.
Note you have a wide flexibility dates, amounts, quantities, discount, etc.