All of the programs on the list, that
rookie147 provided a link to, are used by our members.
They're all good programs that are spyware/malware free, and Free.
Choose only
one Antivirus,
one Firewall, and all of the spyware programs that your system can handle.
Using more than one AV, or Firewall, will cause conflicts, rendering the programs ineffective.
The Sygate firewall, is a free firewall, for unlimited use.
For AVG, there isn't much difference between the free, or paid versions.
You can compare the differences at the link
acklan provided.
Most use the free version, like me.

Why pay for something, if you don't have to?