You can either purchase it online, with your credit card, or you can use a 12 month gold, but you do need gold to play with other users, with xbox LIVE silver, you can purchase downloadable content and addons etc.
2 years ago
Last edited at 7:04PM on 11/19/2011
If you purchase xbox live via the marketplace on the console be sure to call in to deactivate month by month billing after your subscription ends. Unless you would prefer it to kick in after purchased membership expires it costs more and you donit get a option when making purchase through marketplace.