Some people are using avast antivirus with understanding that it is best (may be it's really best). So for those people here I have a trick to get Avast Antivirus License key for free.
After some researching on google I found a new dork that will help you to get free lots of license key of Avast Antivirus.
» Just goto Google.com
» Search for "filetype:avastlic" (remove quotes).