Purchased Norton Internet Security 2010 from Costco Haydock yesterday for £17.27 which is quite a bit cheaper than half price. They also had Kaspersky 2010 available for £16. I assume the offer would cover all Costco's as they all seem to price items the same (I visit Liverpool and Haydock branches regualarly).
I know this isn't exactely widely available as it is Costco so sorry to those who aren't Costco members.
I also know there is lots of debate about how good Norton is and the availability of free alternatives on the internet (although I believe they aren't as comprehensive), but for those people who want to purchase the software this seems to be a very good deal.
I have the receipt but as a new member to the forum I seem to remember seeing that you can't post pictures until you have reached 10 posts? If there is a way of doing it I'm happy to post a picture of the receipt later today after work.