The offer link
https://www.microsoft.com/en-us/groove/plusthree.aspx
Offer ends 12/31/16. One 30-day trial and 1 free promo code to be applied once free trial is completed. Signup requires a valid credit card. Before completion of the first trial month, customer will receive a promo code to be applied for 3 months of Groove Music Pass. Customers eligible for a 30-day free trial will not be billed for their first month of service. Previous Zune, Xbox or Groove Music Pass trial customers are not eligible for this offer. Offer valid from 11/18 – 12/31. Groove Music Pass sold separately and in selected markets. Catalog size and availability varies by market and over time. Microsoft account and internet required; ISP fees apply. Works with Windows 10, PCs, tablets and phones, Xbox One and Xbox 360, Sonos, Andriod and iPhone; see app stores. Requires up to 100 MB storage. Download music on up to 4 devices (not available on Xbox and the Web). Stream to one device at a time. Subject to terms (which may change without notice) at microsoft.com/msa.
Note:
After chatting with one of Microsoft Customer Service, the information that I get is, it is also apply to Australian Subscribers.
Microsoft Groove?