Is money earned from marketing company products online, by receiving 15% of the product's price upon completion of a sale, permissible (halal)? And is a Muslim's use of credit cards permissible?

The ruling on money earned from advertising goods depends on the type of goods and the method of advertising them. If the goods are permissible in Islamic law and not a means for pyramid schemes, then the money is lawful. However, if the goods are forbidden, or the advertisements are a cover for pyramid schemes, then the money earned is unlawful, because it involves aiding in sin. Allah says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression" {Al-Ma'idah: 2}.