بسم الله الرحمن الرحيم
(Fatwa: 1064/1072/M=9/1438)
The transaction of selling and buying is done by ijab-o-qubul (exchange of words) i.e. the seller says that he has sold this thing and the buyer says that he has bought it. It is lawful to sell or purchase only the things which are valuable. It is unlawful to sell haram such as pig, and carrion and impure things such as blood and wine. A man can earn profit on his goods as much as he wishes but it is against Islamic fervor to take advantage of someone’s helplessness or take so much profit which is deemed to be unfair in common practice. The seller (owner) should define his goods correctly, if the goods has some defect then he should disclose it and must not swear falsely and should not deceive the buyer etc.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband