You often see companies advertising cashback or money off products or you get a gift for purchasing or they donate money to charity. It is ultimately meaningless as it is simply money off the sticker price. We need a unit that is gained when you purchase some thing. When you buy some thing you cause lots of good things and work for people which is good. It gives people things to do and it coordinates society. You should always be capable of buying food and energy. Your currency of yourself should guarantee this for exchange. So I can go I to a shop and buy anything with chronological or Sam coins. Then the seller gains a marginal benefit based on my labour creative output in return for holding chronological or Sam coins. They have a claim on my output