Is it permissible to buy goods at a certain price and sell them at a higher price in the name of the merchant, with his consent and the customer's consent, provided that a portion of the amount is paid to the merchant first, then the customer pays the full amount to the merchant after delivery, and the merchant deducts the paid amount and returns the remainder to the buyer, especially since the buyer cannot sell in his own name due to not possessing a commercial registration?

Selling in this manner is impermissible for two reasons: First, selling concrete before acquiring and possessing it. The Prophet, peace and blessings be upon him, forbade selling what one does not own. Second, selling a commodity before taking possession and transporting it, which means it has not yet entered your liability. The Prophet, peace and blessings be upon him, "forbade profit from what has not been guaranteed."

However, you can act as an agent for the merchant, marketing his goods, provided that any increase in price above the specified amount is yours, without you purchasing the goods for yourself.