أحسن الله إليكم Shaykh, if i want to sell something like a book, how would I pay Zakah on it?

If you bought the book to read and now simply want to sell it, there is no zakah on it, If you bought it to sell for profit, then when its year completes you value it at its market price and pay a quarter of a tenth of that value, if it reaches the niṣāb alone or with the rest of your money.