All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The buyer is not prohibited from selling the commodity he bought. For example, if a person bought a car, a house, a riding animal, clothes, books, etc., he has the right to sell them; that is to say that he is not prohibited from selling them even if the seller conditions that he should not do so, since this kind of conditions is invalid and the sale is valid.
But, if the questioner means the products that have copyrights, broadcast rights, encryption rights, etc., such as books and satellite channels protected under these rights, it is prohibited to copy them without the permission of their authors. In truth, preserving these rights falls under the category of preserving the incorporeal rights. Besides, they are private rights that should be paid for when using them in a manner that keeps and protects them. However, if someone violates these rights and wants to copy these items for the sake of trading in them, you are not allowed to buy them from him, since this is considered an act of supporting the wrong doer.
Allah knows best.