A 100% safe, secure and protective Anti-virus can never be free. Anti-virus is the programs which protects our data and information from various mal-practices and issues. There are many security and safety issue for our system or PCs. If it is not monitored by good anti-virus, we may lose the important data or stuff or even our system may suffer in many ways.
There are many good and top rated antivirus program. And all of them are not free, yes they offer us the trail version to use and get experience of anti-virus for 30 days or 90 days. Any antivirus which can really assure us cent percent safety and security can't be free. To protect our system from various problems, all the antivirus developers work day and night so that they can resolve all the latest and updates virus/worm and trojan.
Everyday there are millions of malware/adware/worm/virus/trojan are developed. If you're connected to Internet then you are prone to get effected by any, Here comes the antivirus which really watch for all virus/trojan/worm/malware and it alerts you and then it takes the appropriate actions. Yes, One should always use the licensed version Antivirus. Licensed version antivirus offers you great safety and security for your system or PCs.
As far my own experience of using Anti-virus, Here I'm going to publish the list of best five antivirus rank wise(star out of 5). It is solely on my own experience of using anti-virus :
1. Kaspersky - *****
2. Comodo - *****
3. Essential - ****
4. Avast - ***
5. BitDefender - ***
"People says 143. I say 444 i.e. Love Your Life"