No, unless u buy a runescape game membership card. When u buy the card the membership is like yours. Also when u buy a membership card, they're 1 month mems to 3 month mems. When u buy the membership card, there is a activation code on the back, you can use this code to activate your membership on the Runescape website.
Yes. Here's the official answer from Xboxlive: Q:Can I use a code from a prepaid card to renew my current membership? A: Yes.When you enter a code from a prepaid card to renew your current membership, your membership will continue through its current billing cycle. At the end of the membership term, your membership will automatically renew to the membership type determined by your prepaid card. You will have effectively "stacked" time onto your membership.
You have to pay for the card. The price of the card is your fee. The card can get you a membership for a certain amount of time, but after that if you want to stay a member, you have to pay a monthly/annual fee, depending on what kind of membership you have, bronze, silver, or gold. (all three types of members have the same benefits, though.)