I say, and with God's success: You must pay its zakat; because the purchase is considered a voluntary cause of ownership, and it is accompanied by the intention of trade at the time of the cause of ownership, which necessitates zakat on trade goods. Zakat is only obligatory if it enters the ownership of the buyer with the intention of selling it, unlike if you purchased it with the intention of renting it or acquiring it to sell in the future, as this does not constitute an intention of trade; because the relevant time for the intention is at the time of the cause of ownership, and at that time, your intention was for renting or acquiring, not for selling. And God knows best.