Personal anecdote:

I had the Sirius/XM "Family Plan" + "Internet" option last year, and the total for both was $197/yr. They tried to auto-renew me, but I'd deleted my CC info from their site, so the auto-renew failed. I hate that by the way. (auto-renewing by default).

I called them up tonight, and it went something like this:

Me(English): "Hi, I like the service, and I'm thinking about renewing for another year, but I'd like a discount from the regular price."
Them(Bangalore): "Sorry, we can't do that." (I think that's what they said)
Me(English): "Ok, Then I'd like you to cancel my service completely."
Them(Bangalore): "Please hold while I transfer the call".

--call dropped--

So now I'm*****ed, although I should have expected the dropped call. I try again, this time calling the "cancellation" number rather than the customer care number.

Me(English): "Hi, I was trying to cancel my service, but the call got disconnected."
Them(English): "I'm sorry to hear that, was there a particular reason?"
Me(English): "WTF?"
Them(English): "Pardon?"
Me: "You speak English!..."
---
Me: "Anyway, I told the other rep that I liked the service, and I was thinking about renewing for another year if I could get a discount, but they said no, so I'd like to cancel the service."
Them: "How about 50% off?"
Me: "Deal! Can I pay it right now?..."

-- Happy customer retained: +1 --

Bottom line: They seem to be very flexible on price right now, if the right keywords are presented. I'm guessing it was "discount or cancel".

We've only got XM with my wife's car. I went ahead and got her the XM for life deal a while ago. It fluctuates on what they charge for lifetime; sometimes they've got deals. I think we got it for a bit under $500.
I've got Sirius in my car but haven't paid for a subscription yet. I'm still debating; I've been pretty happy with the radio stations here in Tucson.

I've had it for about one and a half years now. I really enjoy it, and I think it's great value if the price is right.

I spend about two hours a day in the car, and I stream it to my phone at work. I absolutely can't stand commercials, and the local radio stations here don't appeal to me.

I basically listen to one channel 95% of the time (Spa). For $100+tax for a year, the price was right (for me). I might have renewed at $200, but it wasn't a guarantee.

Do a search on lifetime subscriptions. Figure out what you'd be willing to pay. They run specials on lifetime subscriptions from time to time.

Last I checked it was around $500 as well.

Also, at that time their financials were horrible, so I wasn't willing to risk getting that and then having them go TU.

Back in February I called the day before my subscription was to be auto-renewed. Told them times were tough and couldn't afford it. They gave me a discount right away. That's two years in a row. Put a reminder in my cell phone to call before it renews.

The lady told me the last six callers she had cancelled. She wasn't having a good night.

The Obsidian Jedi Mind Trick(aka use of keywords and tone of voice) also work in a similar fashion on Direct TV and Sprint. Being PO'd and seeming to "not give a ****e" about continuing their services helps also.
Customer retention seems to be Job One.