Just enter your email to get 6 months (183 days) of Bitdefender Total Security 2018 (5 devices) for free.
Got this from Raymond.cc - https://forum.raymond.cc/threads/bitdefender-total-security-...
Note: The website states that it will take up to 24 hours for the email because of technical issues.
I have expired the deal after reports that it no longer works. You can still try it if you want.