>I don't understand how they ever make any money, if, as you and other(s) say, the free version is totally satisfactory. Is it that the updates to the risk database isn't as regular/up-to-the-minute as it could be?

Here some details on free version
http://en.wikipedia.org/wiki/AVG_Anti-Virus#AVG_Free_Edition

Here are some freeware and free (open source) alternatives
http://en.wikipedia.org/wiki/List_of_antivirus_software#Freeware