It was a good idea to buy indulgence for sins committed in the Middle Ages. As time went on, humankind dropped the idea of buying expiation for money. However the idea survived through the ages and found a new expression in the market economy. The idea lacks inventive level or novelty but some people all the same are lured into believing that there may be something in it. It is like a Ponzi scheme: people plunge into the adventure, come out befooled, some time passes and other people believe they will have a better luck.