What is the ruling of Islamic law on earning an income from a company by attracting other people to register in it, so that points are earned whose financial value increases with the number of registrants?

It is forbidden to participate in a company's marketing scheme that requires the expenditure of money with the hope of profit, because it falls under gambling, as the participant is either a winner or a loser. However, if the scheme is free of subscription fees, and the product is worth its usual price, and the purchase is intended for personal use and not for marketing participation, then there is no harm in that. The sale of goods and their profit is permissible, and brokerage for a known commission is allowed.