You don't have to pay. It's free on YT. They get money from ads. It's a system that used to be called Google AdSense. Advertisers pay the Youtuber to place ads on their channel. The more traffic you get, the more money you make. I was small time before I got copyright strikes making $20 a day which came out to $600 a month. Some guys with over 200k followers are making $200 a day