ما هي أنواع البيع الحلال؟

Permissible selling is that which fulfills the conditions and pillars of a valid sale, which are three: The formula (offer and acceptance), the contracting parties (who must possess legal capacity and consent), and the subject of the contract (the sold item and the price), which must exist, be pure, have lawful utility, be deliverable, and be known to both parties.

As for prohibited sales, they stem from usury (riba), fraud and deception, ignorance (jahalah), and undue influence (taghrir).