I recently got a letter in the mail after I got my car serviced from the dealer from SiriusXM. They have a reward for my "loyalty" but it seems to work on any car that currently has an inactive account. I just tried this on 3 of my cars that have SiriusXM radios and worked on all 3. You don’t need a credit card and it automatically cancels after 2 months. You get all the channels including the premium ones.
http://siriusxm.com/startmytrial1