Q: I own a store and sell various physical products, do I have to pay zakat on the products?
A: Yes. Zakat must be paid in cash, after the completion of 1 Hijra year, based on the current market value of your commercial inventory if the following conditions have been met;
1. The total market value reaches the nisab of whichever is lower of either gold or silver.
2. You intentionally obtained the products.
3. Your intial intention for the item was for the purpose of trade.
Source: Hidayat al-Raghib