One big hosting provider is acast.com, a Swedish outfit. Their service is free with the disclaimer "let us worry about how to make money." That's kind vague, but they seem to insert ads into your rss feed or program, then spit the revenue with you. How much control over the ads do you have? I don't know. It's also a little fishy to me that one of their featured podcasts hasn't been updated since 2015, with the last episode saying "We're moving to Libsyn." Rule #1 of advertising is "Never send a customer to your competitor."