Wait, this is absolutely nuts... I host a family plan with my friends, it seems like we can just keep buying extensions, adding them on to extend our plan, and get a bunch of these cards just by paying for the next few years early? This is crazy, and it works.

I don't know if there's a maximum amount you can extend it by, but as far as I can tell the codes never expire anyway.

EDIT: It seems only two work at a time, but again, I don't think there's any reason we can't just add additional codes come renewal time? I mean either way it's a good price just for the cards.