Browsing the AU Xbox LIVE dashboard and came across this deal. Purchase with PayPal and cancel auto-renewal right away. I have done it before and it is far easier than removing a credit card.
Just to clarify - you purchase this from the consoles dashboard, not via Xbox.com.
The ad/offer is only available to members who are currently using the free (silver) service. If you are a paying member, it won't be visible.
To cancel auto-renewal - http://support.xbox.com/en-US/billing-and-subscriptions/subs...