In the Name of Allaah, The Most Merciful, The Ever Merciful
All perfect praise is due to Allaah, the Exalted, Whom I ask to Confer peace and blessings upon the Prophet.
Some companies offer free gifts for the consumer, along with the product which the company wishes to market, and set a certain price for such an offer. Some vendors split this offer and sell the product solely to the consumers while taking the free gift for themselves or selling it for a certain price. What is the Islamic ruling on such an act?May Allaah Reward you.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

If this vendor bought that product and owned it along with the attached free gift, there would be no harm if he sells that free gift by itself or uses it for himself; for he owns it and he has the authority and the right to dispose of it, whether by selling it or by using it himself.

However, if this vendor was a distributor of the company who distributes its products and takes a fee in return for that, and was not a mere buyer, then it would be impermissible for him to sell the free gift by itself instead of selling the company’s offer as one package; since such an act would be counted as a breach of trust that implies violation of the company’s conditions.