What is the ruling on selling rare coins, whose existence is scarce in the world, for a value of 800 dollars per coin, with the option of paying once or in installments, and allowing the buyer to market the coin and receive a 5% commission when bringing in ten customers?

It is not permissible to deal with the company "Gold Search" due to its practice of selling that involves prohibited matters, including: not delivering the purchased currency until ten customers are brought, along with taking 5% of their money. In the event of inability to bring them, the buyer only recovers half the amount. This condition contradicts the essence of the contract and is considered consuming people's wealth unjustly. Furthermore, the company sells gold currencies in installments, which violates "selling gold for gold," a transaction that requires immediate possession in the same session. In addition, the payment of money to the buyer is not for the purpose of purchase but to obtain 5% of the customers' money, which is a form of gambling due to the possibility of it not occurring. Thus, the transaction involves gambling, risk, and prohibited usury.