Listmonk

Listmonk is open source newsletter software you run on your own server, handling list management, campaign sending, and basic analytics without per-subscriber pricing since there's no vendor billing by contact count.

It fits podcasters who already run other self-hosted infrastructure and want to avoid the recurring costs of a hosted email platform, especially once a list grows large enough that per-contact pricing elsewhere gets expensive.

The tradeoff is that deliverability, the hardest part of email, is entirely on you. Setting up proper authentication and maintaining sender reputation without a managed provider's infrastructure takes real technical effort.

A good fit for the technically inclined who value ownership over convenience, not a good fit for someone who just wants to write and hit send.