How do podcasters make money?

So, I've been curious about how podcasters actually generate revenue for their shows. I understand that advertising is one way, but are there other methods as well? How do they determine how much to charge for sponsorships or advertisements? Do they need a large audience to start making a significant income? I'm especially interested in how niche podcasters might be able to monetize their content. Could you elaborate on these points and give me a comprehensive overview of the different ways podcasters can make money?