What price are you expecting to pay?
Forgot to mention, I am using Windows 8.1 64 bit.
I think it likely that the version of windows you have is more likely to have vulnerabilities given Microsoft has stopped the mainstream support for it and total support ends in 2023.
Given that, I would be inclined to :
Upgrade to Windows 10 and use one of the free (less expensive) software options
or
Upgrade to Windows 10 and use one of the free (less expensive) software options
or
Stick with a free/cheap option and hope for the best.

I have been using the free version of Avast for a few years on two computers with no problems.you should upgrade from W8 to W10 and you can still do so for free.
www.superantispyware.com
My experience of this - before the turn of the century - came from the guy running a studio full of Macs - "We don't use antivirus it just slows Macs down and they don't get viruses like PCs"Do people still recommend that Mac users should not be overly concerned about not having an AV program installed?

My AV software occasionally tells me it has thwarted a nasty attack but how do I know. It may just randomly generate such messages form time to time to make you feel you have done the right thing.
And I've not seen a AV program that woks with Big Sur on a Mac, so even if you wanted some AV, I don't believe there is one that works!I've always had that suspicion.
SophosAnd I've not seen a AV program that woks with Big Sur on a Mac, so even if you wanted some AV, I don't believe there is one that works!
MalwarebytesSophos
Back in the early 90s I had a virus that wiped the hard drive so since then I've been using AV.Are they really worth it. I have had no issue with viruses over the years, just some care in what sites you visit and what you click on is needed.
I've told this story before. Many years ago I held an IT Management position at a large supermarket chain. In a meeting the topic of in-store fire sprinklers came up. The MD at the time said that he was against them "because we've never had a fire".Are they really worth it. I have had no issue with viruses over the years, just some care in what sites you visit and what you click on is needed.
I get that but are these paid ones any better than the one included with Windows is what I mean?Back in the early 90s I had a virus that wiped the hard drive so since then I've been using AV.
Yes being careful about which websites to use helps but a few well known companies have had malware spread from their servers.
Another thing to keep in mind is that the sites use https rather than just http should in theory, be very secure.