How is the zakat calculated for a shop selling herbs, ointments, and natural oils when a year has passed, given that there is unsold merchandise which may expire, or accumulated merchandise that is distributed for free for promotional purposes?

Goods prepared for sale are considered trade goods, and zakat is paid on them by valuing them at market price when a year has passed. If their value reaches the نصاب (minimum threshold), a quarter of one-tenth (2.5%) of their value is to be given. As for unsalable goods, zakat is paid on them just like other salable goods. However, goods intended for donation as a promotional strategy are not included in trade goods because they become acquired possessions. Medicines that have expired must be disposed of in a way that prevents harm.