AVG (commercial version) can be used for any PC and has no restriction on commercial use. There is a good summary on the AVG Free Edition product page (
http://www.avg.co.uk/uk.product-avg-...s-free-edition).
The AVG engine is the same, however the free edition tends to be less flexible on scheduling and updates, but in a home environment you don't need such frequent definition updates. The commercial version has additional features such as spam filtering, download scanning, firewall and so on.