Antivirus & Firewalls - Your opinion wanted

Why use software that costs money ? theres so much great freeware stuff out there , personally i use the sygate firewall and no virus scanner at all , if i need to scan i use trendmicro online scan and my common sense when dling stuff and surfing .

i also use firefox only , have adaware, spybot and Spywareblaster installed and also dont forget to close uneeded services in xp ie dcom and pnp , xp antispy is also installed so thats about it