One advantage paid security software has over free software is the security suite. A suite has anti-virus, anti-spyware, a firewall and a bunch of other features in one integrated package.
You can do the same thing with free software, but you have to download the programs individually and they're often made by different companies. You could be missing something important and not even realize it!
Agnitum solves that worry with its free Outpost Security Suite Free. This powerful suite contains integrated anti-virus, anti-spyware and firewall.
It also has anti-spam filtering for your email and can tell you if a site you're visiting might be dangerous. Plus, it watches your computer for possible infected files and programs.