I've gated narrations at the minute outside of trials as each narration costs me money to create, but currently I have the functionality to use the mobile devices sharing feature to bring sites into the app, from there you can request narrations on individual articles.
Interesting point on audio books though, I might look into creating a single narration for batches of articles in the same way I currently do for PDF/EPUB.
Interesting point on audio books though, I might look into creating a single narration for batches of articles in the same way I currently do for PDF/EPUB.