What is the ruling on paying a sum of money to purchase specific goods with an additional fee for packaging and delivery, whether the price is itemized or not?

Agency in purchasing, packaging, and delivering a commodity for a known fee is permissible in Islamic law.

However, it is not permissible to conceal the true price of the commodity. Rather, the principal must be informed of the amount of the fee, because the Messenger of Allah (peace and blessings be upon him) said: "The wealth of a Muslim person is not lawful except with his willing consent."