Let's answer your questions one by one, shall we?
Is paying for any of the free antivirus software worth it for home users? If so, which?
I think it depends on the individual - mostly on how they use the machine. Without proper safe surfing then there is no software in the world that can save you from infections.
A free AV combined with an AM (anti-malware) solution and the Windows Firewall is enough for users in most cases.
In my case, I use a laptop and have to travel, so I use a security suite (which is an AV with more functionalities).
For small business? Router/Hardware firewall? SaS? Affilliate/Partner programs techs are happy with?
I will leave this question to someone more knowledgeable in corporate security
my knowledge mostly applies to home users.
Remote virus removal? By hand? Using combofix remotely?
In case you haven't noticed already, the Bleeping Computer Study Hall offers malware removal training
And the use of ComboFix without supervision is very dangerous. You can read more in here