Hooray!
I ran a network of 2000 PCs for 10+ years with no anti-virus software. It's one of the purest examples of a problem that barely exists being fixed by a product that doesn't work. I saw an interview with John McAfee where he admitted that he didn't use any AV software.
Of course, malware in general *is* a huge problem. But almost all successful malware relies on exploiting bugs in the operating system, which is not what most AV products protect you against --- indeed, they can't, because the AV software companies don't know where the next critical bug is any more than the OS makers. (Or they do, but the OS makers refuse to patch it, as happened when WannaCry trashed a lot of Windows XP systems earlier this year. Do you remember any anti-virus software companies telling you how they saved you? The UK national health system's AV company, Sophos, had to remove the NHS as an example of a big organisation it was "protecting" from its web site, because it catastrophically failed to protect them. Yet for some reason, people forgive AV software even when it fails them time and again.)
The problem is that the model of the "evil virus that will infect your files and destroy your PC", which kicked off the whole AV industry 25 years ago, is so persistent, even though such viruses are basically extinct; where it's at now is worms, which are basically orthogonal to viruses and are immune to typical AV software security scans. Malware is now a billion-dollar (underground) business, based on sitting there and quietly using a percentage of your PC's resources. It has no interest in doing much damage to your computer; rather, it's basically a parasite whose interest is to take what it needs from the host without killing it (and, ideally, without the host --- which means you and your PC together --- knowing the parasite is there).
Your money is far better spent on a premium subscription (if you have lots of data; if not, the free deal can be fine) for Google Drive or Dropbox or OneDrive, or perhaps giving $20 to a friend to configure a nightly backup of your main data. By far the biggest cause of data loss is physical theft of the computer (especially laptops), followed by hard drive failure. Backups protect you against those as well as the (mostly mythical) Evil Virus That Trashes Everything.