I have 3 computers at home. Can I buy the single user version of Macafee antivirus software and use on each computer using separate email addresses to register?
I have 3 computers at home. Can I buy the single user version of Macafee antivirus software and use on each computer using separate email addresses to register?

No, obviously not.
It is against McAfee’s End User License Agreement.
Doing that will make your McAfee copy considered as ‘pirated’.
Buy a 3-user license instead.
Hope this helps