I had a spare number that hadn't had Apple Music on it before, so I got another free 6 months, and then promptly downloaded 3GB of albums quota free onto my Android Phone (again, Apple Music is SO MUCH BETTER in the Android app, since it's completely separate to whatever other music you have on the device).
Also, a little tip for the Appletalkers: If you have multiple Telstra Services, you can use each one to get another 6 months of free Apple Music, but you need to do this manually every 6 months (while this offer is still active). So you're probably still on the original 12 month offer right now. Make sure before the 12 months is up that you go into Telstra My Account and cancel the free offer otherwise you'll pay for Apple Music after the offer expires.
Then what you do is go into another Service you might have (and it would appear data share SIMS are eligible as well) and Activate the 6 month offer.
Just make sure you cancel it before the 6 months is up. Then if you should happen to cancel the data share SIM, and reconnect a new one with a different number, you should be able to get another 6 months