Your parents can't fill up an Amex account (and neither can you). It is a charge card (some of them are credit cards). You apply for a card, and if you have a good enough credit rating, you will be issued a card and have an Amex account set up for you. You (and any supplemental cardholders you designate) can spend up to your monthly limit that Amex has given you. At the end of the 30-day billing cycle Amex will deduct from you bank account what you have spent (in the case of an Amex credit card you pay a minimum amount or more). You cannot pre-pay. I don't specifically know how Amex works in Norway, but I suspect it is the same as in the rest of Europe.