What is the ruling on brokering trade between a seller and a buyer, sometimes using the name of the purchasing company, and is it permissible to increase the original price of the goods, given that the seller and buyer are from different countries?

If the purchasing company authorizes you to make purchases, it is permissible for you to take a fee for that with their consent and using the company's name, because agency and brokerage for a fee are permissible according to the majority of scholars.

However, it is not permissible for you to increase the price of the commodity, because you are entrusted and must act in the interest of the party you are working for. You are only allowed to receive the agreed-upon fee.

It is not permissible for you to use the company's name for your personal purposes without their permission. However, if you purchase the item for yourself and take full possession of it, it is then permissible for you to sell it for more than its price, according to the agreement with the company that wishes to purchase.