I don't know about other subscriptions other then Sirius/XM, so:
if the SAV never had the satelite radio on, you will get a year for free (in most cases).
Outside of that there are diferent packages and, one I have, music only is about $13.00

Good Luck to you.

PS: I have Sirius in two of my cars and would not know what to do without it anymore. (unless you get a USB drive or iPod, iPhone type device)