I am sure that most existing Sky customers are aware of the Benefits of continually asking for discounts, but if not you can usually obtain half price discounts for 6 months or more on the Sky Hd channel, Sky multiroom and sky movies (and other sky channels no doubt) if you are an existing customer. You just have to ring up and ask for them!
If you have not done this to date just ring up sky customer services and press the option to leave sky or to drop sky channels. When you speak to an advisor be polite and say that your sky bill is becoming too expensive and ask if they can offer you any discounts on the package that you have, they will not usually discount the main package but will discount any add on channels such as the channels mentioned above. Advisors have told me that they are only authorised to apply one discount per telephone call. You simply ring back up again and repeat the process until you have obtained half price discounts on all your add on channels.
Make a note of when the discounts run out and then ring up at the appropriate time to repeat the process.
I have today got discounts of nearly £20 per month over the full price of Sky multiroom and the add on channels (sky HD and Sky movies)
I hope this helps.