I got a truck last September and it came with the free XM trial. Trial expired, I looked at the prices and decided I wasn't going to pay the $15/month whatever they wanted for it.

Last night I stumbled across a deal where if you have a radio that's not active, you can get 6 months for $24.99 plus a $2 royalty fee. $27 for 6 months isn't bad, so I signed up with it. Didn't have to talk to any customer service reps and radio was working within 5 minutes of completing the online form. YMMV, link below. Good luck!

Link - You'll need your Radio ID and account number