you need to either go to a store and buy a pre paid card or go the cheaper option and buy one online.
www.gamecard.com.au have a deal on at the moment where you can buy a 12+1 month xbox live subscription for $45.95 which is a great deal and you receive it with half an hour of paying straight into your email inbox
You can also get your sub off this website or your xbox but you will need a credit card and it will set up to renew automatically if you dont change the settings.
super dog!!!
