What is the ruling on benefiting from the service of deferring the payment for a product on e-commerce websites for 20 Riyals upon receipt, especially if some websites only allow payment via bank cards?

The seller's setting of two prices for a commodity, one for immediate payment and the other for deferred payment with an increase, is permissible in Islamic law, provided that the contract is concluded based on one of the two prices, and the price and the term are specified at the time of contracting.