The points which are bought by a store owner often mean the number of sales his store can do. For example, somebody invests $200 for 800 points. The points are what the store owner sells and redeems to his customers. When a customer purchases $20 from you, then 20 points are removed from your points total balance of 800. The customer then can play out his points.
Every game is not similar. They are different. If a player wants to make a spin or a move, he needs to pay with his points. If customers win a prize, they can either continue playing until no points are left, or redeem their winnings. So let's say one of your customers chooses to redeem 10. The store owner would redeem the customer 10 points and the system would then add 10 to the existing balance in the store owner's bank of points. (Starting points) 800 - 20 (sale) + 10 (redeemed) = 790 left in credits.