Big companies wants your business and they want you to try their product for free. Specially if you are home user. Here are some of the best freebies and — most important –where to get them.

• Avast! Home Edition
  avast! antivirus Home Edition is available free of charge for non-commercial home use ONLY. If you are not a home user or if you use your computer for business purposes, please download the avast! Professional Edition.
• AVG Free Edition – Download the most trusted free antivirus and antispyware security software for Windows 7, Vista and Windows XP
• Malwarebytes
  Malwarebytes is a site dedicated to fighting malware. Malwarebytes has developed a variety of tools that can identify and remove malicious software from your computer. When your computer becomes infected, Malwarebytes can provide the needed assistance to remove the infection and restore the machine back to optimum performance.
• Ad-Aware Free
  Ad-Aware Free Anti-Malware features real-time protection, a rootkit removal system, automatic updates, and much more — to ensure that you have the power to protect yourself online.
• Spybot – Search & Destroy
  Searches whole computer or just a certain file for malicious software commonly missed by anti-virus programs. Can be used to clean usage tracks.