PRX offers two different delivery methods: manual download and automated delivery. The latter is a paid service that producers can opt-in to for their series. If a producer has decided to use automated delivery, then you will see a large blue button that says "Subscribe to series for WXXX."
If you see a blue button that says "Buy piece for WXXX," then the automated delivery feature is not enabled for that series. If you would like a certain show to be delivered automatically, we recommend reaching out to the producers directly to encourage them to use this service.
You can learn more about automated delivery here.