What is the ruling on taking a commission for purchasing a gift card online using a credit card on behalf of individuals who do not possess a credit card, and is it permissible for the commission to be a percentage with a minimum or a fixed amount, and how is the price calculated if the website's currency differs from the currency received?

Credit cards often contain Sharia (definition)-prohibited elements that prevent their use. If your card involves usury (riba) or impermissible conditions, it is not permissible to use it or trade with it. However, if it is permissible, it is allowed to use it to charge it with one currency and receive another currency, such as dollars for euros, provided that the exchange takes place in the same session of the contract, based on the saying of the Prophet, peace and blessings be upon him: "If these different types are traded, then sell as you wish, provided it is hand to hand." But if the currencies are the same, it is not permissible to exchange them with a disparity in amount.