Pyramid scheme
Such "businesses" do not have real products or services. To make them more believable, most such scams have fake letters from successful members and information. Only the first person (sometimes called the "pharaoh") and a very few at the top levels of the pyramid make a lot of money. The amounts get much smaller further down the pyramid. Someone at the bottom of the pyramid loses money. They paid to enter, but cannot get anyone else to join.