I protect my computer for free! And it works. A lot of the reason computers get bogged with spyware, viruses and other trash has to do the users frequenting questionable sites. Even a careful internet user can find himself in pernicious territory. That's why every computer with an internet connection should have some sort of anti-virus/anti-spyware tools and a firewall. Parental controls/Internet filtering tools are optional, but also quite helpful in warding off attacks as well.
It's been about a month since I started using Open DNS for internet filtering. I have been very happy with it. I have noticed that I'm a bit of a sloppy web surfer. I tend to click before I look at the address to find out where I am going. Quite a few times I have been saved by Open DNS or my Web of Trust (WOT) settings. The nice thing about all of this is, that if I really want to get on a blocked website, it's easy to do, but the warning is nice. I've only had one instance where I actually did want to view a blocked site; all I had to do was go to the Open DNS website and put the website url on my safe list. EASY.
So, in a nutshell, I've been able to make safer surfing, while protecting my computer from spyware/malware and viruses all for free by using: AVG Free (does NOT slow down my computer during scans, unlike Norton), Zone Alarm (Free version firewall), WOT and Open DNS. Why pay when you can get it for free? Check 'em out.