I get Sirius everywhere for like 10 bucks a month - all stations I believe. The key is pay for an internet subscription only and just use the Sirius App on an IPhone. I have those "headphone jack"/8mm(?) wires coming out of both my cars sound system and in my garage. Everywhere I am, my iPhone is as well, - so I always have Sirius.
The Sirius App has surpassed the radios in performance in the past year or so. I never have "breaks" or "searching" anymore. Now it works flawlessly.
I ditched those crappy radios the sell about 5 years ago after the 4th or 5th antennae broke for me on a trip to Canada. Of course, if you have the radio as part of you standard installed sound system in your car, I can see it's pretty tempting to get a subscription for that car. But, a lot of cars now come with factory jacks for MP3 players. If not, they are available in the aftermarket. You'll get your money back for a purchase of these in a year or so with the money you pay for subscription fees.
I'm not sure how the radios work now, but when I had them, you got all the channels for one price. Now I believe they nickel and dime you for packages.