As per the title, my cousin has an unknown region gamertag/account on his Xbox (or at least, I'm not sure about it 100%).
I want to get him a 12 month Gold subscription so he can join me in online gameplay for Christmas (reason why I'm not sure).
How would I go about verifying the correct region for the prepaid card purchase? Or do you get ones that are valid worldwide?
Supposedly prepaid Gold cards are region-free, although Microsoft controls this and their stance is:
Some prepaid codes can be redeemed only in the country or region in which they were purchased.
... which is extraordinarily vague, likely on purpose.
You might want to contact Xbox Live customer support before spending any money - it's generally very hard to get your money back from these prepaid cards. Also, counterfeits and completely fake codes are extremely common from less reputable sellers, so beware any crazy deals or promises from vendors.
