There's one-time purchase fee when buying the gift card itself. Usually from 3.95 and up.
Cards are only shipped within borders of US. By letting someone else doing it for me (In US), I would have to compensate for their wasted time-> so nope.
There are other options though. Like virtual credit cards. A good investment would be buying multiple of these, and really only making an account per 3-4 day interval. This way one could squeeze decent sum of accounts before automated anti-fraud detection hits a bell, or if it does. Should e-mail jagex and question them when the offer ends, LOL.