I use AVG free.  It does on occasion offer to sell me the "full" version with all sorts of bells and whistles.  Things which from experience tells me my computer will not be safer and will be slower.

But, AVG has done a great job.

I also have Malwarebytes free and it's not running in the background, it only runs when I tell it to.  I usually boot into safe mode once a month and run Malwarebytes then so it can find things that might hide when running windows normally.

I also run COMODO free firewall. 

To date, running my PC computers since 1981I've had one (1) virus.  That was many years ago when I was sent an email with a see this gif.

I also run AdBlock Plus and Cookie Remover by Adam, and for those pesky pages that you can't see without a subscription I've found Firefox seems to have a built in toggle reader view by hitting F9 on pages from magazines and newspapers or I can use Tranquility! readerhttps://github.com/ushnisha/tranquility-reader-webextensions

I have repaired or cleaned many computers only to have the owners have others remove files and programs to make the computer run faster or install programs to make their computer faster or safer and then I get the annual call to clean up the computer because it's running slow.