Is it permissible to agree with a merchant to reserve an item at its current price in exchange for a sum of money to guarantee its price for a specified period, such that if I buy the item, I pay its agreed-upon price, and if I do not buy it, I forfeit the amount paid?

This transaction resembles option contracts, which are invalid because they represent compensation for the seller's commitment to sell at a specific price within a known period. The subject of the contract (the commitment) is neither property, nor a usufruct, nor a financial right. The Sharia-compliant alternative to this is the ‘urbun (earnest money) sale, where the total price of the commodity is 1020 Egyptian pounds, and 20 pounds are paid in advance as earnest money. If the buyer rescinds the contract, the seller is entitled to the earnest money. The ‘urbun sale is permissible if the waiting period is limited to a specific time.