What is the ruling on taking a 3% commission of the value of goods for office services, and 6% if the office pays part of the value of the goods from its own money?

The Sharia permits a percentage taken in exchange for services, because it is a known wage for a benefit. As for a percentage taken in exchange for paying part of the value of goods, it is not permissible, because it is considered a loan that draws a benefit (usury), and it combines a loan and an exchange, which the Prophet, peace and blessings be upon him, forbade with his saying: "A loan and a sale are not lawful."