Donating to skip Icecrown queue - how does it work?

Hey, let me start off by saying I'm completely new here, so I don't know if this is the right/wrong place to post this, if it is, please redirect me to it.

Me and my friends really want to try out a high xp rate wotlk server, and we thought Warmane would be the best server for it. We found out that there often is a log-in queue, and that you have to donate to skip it. How does that work? Like, do I just buy 10 coins from the donate store and I can skip queue? Should I be online when I donate? And I have seen alot about Subway $10 gift cards, what's the deal about that? Is it not possible to buy coins through paypal? And if so, why does people use Subway gift cards?

once you donate, it does not matter how much, your account become "premium".
As perk you will skip Icecrown queue forever.

No, it is not possible to donate via paypal.

What's the easiest way to donate when you're from Europe? I've never used gift cards before, which options are there to use?

I just made a purchase using my bank account. That's pretty easy.