Is it Islamically permissible to participate in a program that is based on the principle of paying a sum of money to enter a lottery for the chance to win a specific product, given that the money is returned to the participant in the form of a purchase coupon from the same company if they do not win? And what is the ruling on products that have been won from this program previously?

The described method is forbidden because it is a form of gambling, as the participant pays money for a chance to win, and in the event of not winning, they are given a coupon that they may not need. This is a case of "certain loss and potential gain."

Furthermore, paying money before the draw is forbidden because it is considered a loan from which benefit is derived, and combining a loan with a sale is forbidden, as the Prophet, peace and blessings be upon him, said: "It is not permissible to combine a loan and a sale."

If a person obtains a product through this method while knowing it is forbidden, they must donate the remainder of the price as charity. However, if they were unaware of the prohibition, then what has passed is theirs, and they are not required to donate anything as charity.