There are plenty of free ones though. Are you not using any antivirus at all? What about Windows Defender?
It's on top of anti-virus, but I do have a lifetime license for malwarebytes antimalware on my desktop... but you can't find a lifetime license anymore and I really hate subscriptions for ANY software. MBAM does a good job (sometimes too good) at blocking browser nasties...
Just broke my personal record for number of consecutive days without dying!