Step three: If you have an Android or jail broken iPhone, download a location spoofing app and set your location at a major local car dealer. If you have a normal iPhone you can simply just drive to a car dealership and park in the lot for a few minutes.
Step four: Enter your radio ID into the app, and you should have the same 3 month free trial as if you bought the car used from that dealer. No payment info or sign up required. Once it expires just repeat the process.
I might have felt a little bad about this had they not tried to bait and switch me and several family members multiple times. They will lie about promotional rates, hide fees, and jack up your rate without telling you.
Also, I discovered accidentally if you have an active subscription on a radio or vehicle you aren't planning on using for awhile, you can cancel (good luck) and it might still be active months later without the subscription. This has worked twice for me in the past, once on an old aftermarket stereo with Sirius only, and now on my current vehicle with a SiriusXM factory stereo that I happened to have parked for about 6 months. Seems to be permanent, going on 3 or 4 years now without a new bill.
From my understanding, they have to have their satellites send out a 'kill signal' specific to your radio that it receives to deactivate itself. The signal continuously rotates 'kill signals' to different radios once canceled, but over time the one for your radio will be sent out less and less, until maybe never. Not sure if this would work with a trial activation.