£50 a year is way too much for AV.
AVG Free is deliberately inneffective - get a virus (which you may already have and AVG hasn't detected it) and you'll quickly find out why they offer a free and a paid for version.
MS Security Essentials, free from Microsoft, is actually pretty decent. Especially compared to other 'free' AV apps, and it's much less invasive and bothersome.
I use Avira Premium Security suite (40 euros a year) which is AV and Firewall, Spyware etc although am thinking of ditching it when renewal comes up as the constant firewall popups in Windows 7 are really getting on my nerves, and there doesn't seem to be a way of calming it down without it freaking out about you having your security settings too low constantly.