There's not more protection with free/paid software, it's just more features that experienced security enthusiasts don't need. Free AVs aren't always bad, for some reason people think they are.
I use free antivirus when I can, such examples include Bitdefender Free, Avast, and I have also used and highly recommend Avira. For important computers or ones with very low requires I've found Webroot to run flawlessly and do exactly what I need it for (doesn't use excess resources, very very light, etc.). Plus for $19/yr for 3 devices you can't really go wrong at all in my eyes at that price.
Personally I believe that you shouldn't be forced to pay extra for security however I'm on a Chromebook where all code has to be signed by Google to run so I don't need nor have an anti-virus program.