According to TechCrunch, this is available through Anchor. Podcast hosts will have up to 20 different pricing options for their content, with three prices being available first, and the rest following after. These roll out for US podcasters first, and to the rest of the world on 15 September.
The subscriptions also mean more than just getting access to podcast content. Spotify is also making it so that podcast creators can download a list of contact addresses for their subscribers. This allows them to further engage with their subscribers and offer other benefits. Though the report does not describe the possible nature of these benefits. Overall, probably not the most anticipated feature for Spotify users. After all, most podcasters have other avenues of engaging with their audience. But if you have a podcast that you follow, this is an additional option to show your support. (Source: TechCrunch)