I found this while looking at ways to add some extra time onto my Xbox Live Gold subscription. It's a bit of a hack so bear with me. I also did this while using a private/incognito window in my browser, you may want to do the same so a cookie isn't set that may break the process.
Edit: it appears that if you’ve already upgraded to GamePass Ultimate this won’t work for you. It only works with standard Live Gold accounts.
Edit 2: I see the deal has been marked 'Targeted' per a lot of comments below. I definitely didn't receive an email or notification in the Xbox interface with an offer, I simply found it while browsing the Microsoft store online. So, I cannot confirm it's targeted or not.
- Visit www.xbox.com.au and log into your account.
- Navigate to Game Pass -> Xbox Live Gold.
- Click the button 'Gift Xbox Live Gold'.
- This will open a new tab which shows your remaining current subscription. If it doesn't show the current one reload the page and it should appear then. (You need to ensure the page knows you're logged in.)
- Click on the dropdown box and select 3 Months. The price displayed should change to $10.95.
- Click the 'Extend' button to complete the purchase and agree to signing up for a 3-month recurring subscription, with the next charge due the day after your time expires.
- Click the green 'Manage' button and this will take you to your Microsoft account.
- Locate the Xbox Live Gold section and click the link to 'Manage' beside your subscription.
- At the 'Has recurring billing' section click 'Change' and select 'Turn off recurring billing', then confirm the cancellation.
- Now log out of your Microsoft account. Close and reopen your browser and start from Step 1 again. Repeat as often as you like.
I don't know if there's a cap on how much you can purchase, I stopped at 1 year only because my PayPal account had run dry. Also, if you already have recurring billing turned on for your Xbox Live Gold account you may will need to turn it off first before starting.
Once you've loaded up with Gold time, ensure you also stack it with the $2 Game Pass Ultimate deal, if you haven't already taken that up.
if you want to save even more:
join woolworths rewards with the code that gives 1500 points
buy a $30 students gift card from woolworths that gives you 600 points. use the $30 gift card at eb gsmes to buy $40 of xbox live credit than can be used to buy game oass etc.
you now sldo have $10 of credit on your ww card to buy shopping or another $20 xbox live credit - plus a fuel voucher.
rinse repeat