So here's the deal. A friend of mine came back from NA with a prepaid card. I tried to enter the code on the list, and it said that this payment is not available on the page and is available through the "Purchase RP" page. So I go there and there is no option like this.

Anyone want to explain why the hell don't prepaid cards work for Europe? That's kind of discrimiation towards EU players. And above all- what am I supposed to do with this card? Put 50$ in the trash??? That ain't right...

Same here. I think they don't work because they're two separate servers, with two different sets of codes.

I just checked the NA server. When you click the "Purchase RP" option in the NA server, you will find four options, one of them is pre-paid cards. Seems like they haven't added the prepaid card option in the European server, yet.

help us riot

ya i hav the same problem
is or will there be a way to use them
help us riot

did anyone ever figure out the answer to this problem i just got the SAME EXACT problem today :/

Perhaps if you try sending a support ticket to riot explaining the situation, they may make the code invalid and give you the RP, but no gurantees.
http://support.leagueoflegends.com/anonymous_requests/new

Albull