It is permissible to use credit cards if they are free from things that are haraam according to shareeâah. For more information on that please see the answer to question nos. 97846 and 97530.
If you paid the money first, this is what is known as loading or filling the card, then you can buy the goods with the card. There is nothing wrong with that.
It is important to pay attention to 2 points:
1. It is not permissible to sign a contract with the credit card company if it includes the condition that a penalty be paid in the event of late payment, because this is a condition of riba that is haraam. So it is not permissible to agree to it even if one is determined to pay on time, unless one is forced to deal with it, in which case there is nothing wrong with that, so long as he knows that he is able to pay the amount during the grace period before interest is charged.
See also the answer to question no. 3402.
2. It is permissible for the bank to charge a fee to the seller, but the scholars differed as to whether it is permissible to make the purchaser pay this fee or not. What seems to us to be the case is that there is nothing wrong with that. Concerning this matter please see the answer to question no. 103187.
There is nothing wrong with telling your friends about this card so long as it is free of the matters that are haraam according to shareeâah.
And Allah knows best.