If you have engaged listeners, over time you should be able to convert about 5% of them (generally for $5-10 a month). When that becomes worth it is up to you,

If you have engaged listeners, over time you should be able to convert about 5% of them (generally for $5-10 a month). When that becomes worth it is up to you, but we generally don't see super successful launches for podcasts with less than 10,000 downloads per episode.