I can't afford to pay 20€ per month--that's more than my whole monthly phone bill with something like 50 or 100 GB of data. Cost of living is high enough as it is.
I also lack the most valuable currency there is in one's life, one that you simply can't get more of. Time. So I block ads, which cost a lot of time, with extreme prejudice.
Ads are also bad for my mental health, they just irritate me, rack up stress and easily swing me into bad mood.
Lastly, I don't give a fuck about costing money to some multi-billion corporation. I don't care about them as much as they don't care about me; the corpos see me just as a resource to exploit as much as possible then move on to another one when there's nothing more to exploit, and I see the corpos exactly the same way. Call it mutual parasitism. Yes, I'm a parasite. And parasites are the most successful lifeforms on Earth.