OK, a fuller workup.
Firstly, antivirals. Most AV companies have an interest in hooking you and keeping you hooked, so they keep you paying. I was, in passing, taught how to write a virus by Alan Solomon himself, which goes some way to my supporting the suggestion that some of these companies walk both sides of the street, insofar as it's in the interest of the survival of their company for viruses to continue to be a problem. But to suggest it is a true case of mafia-type warehouse insurance is to go too far, enough problems come out of China's and Russia's governments to ensure the business continues. for myself, I didn't pay for the problem, I rather prefer not to have to pay for the solution, so I use the AVG free variant for viruses.
That solves the need for prophylatic cover. But at the same time, there are less noxious but still unwelcome ads and trackers, and for that I use AdBlock Plus and Ghostery under Firefox. For all that we should support the sites we follow, we already do to some extent in the internet subscriptions we pay monthly. If you want to whitelist the Cat, you can do so, but I mostly see no moral justification for making people rich whose sites don't add much to the wealth of human knowledge.
Apart from anything else, I already know all about what interests me, and I find nothing so irritating as some crap computer program trying to sell me a Chinese rip-off of what I'm about just because they think I know no different.