Amazon.com seems to be doing a big push on this. The 3-PC (Windows) version is (as I type) at $26.99, but it is changing daily. I ordered it a few days ago for $19.99, and it is likely that this price may happen again before KIS goes back up to the normal $39.99 it is usually sold for. I'm not trying to advertise for Amazon, but if I find a good deal I can't help but pass it on.

KIS is a top-ten package. Very solid antivirus, antimalware, and antispam engine, adaptive firewall, and tons of control software, while still lean enough that it won't bog down your system.

http://www.amazon.com/Kaspersky-Internet-Security-2013-Users/dp/B008MR2IDK/ref=sr_1_1?s=software&ie=UTF8&qid=1361385753&sr=1-1&keywords=kaspersky+internet+security+2013