We use Sender.net for our mailing list. This means we have your email address, should you provide it. We'll email occasionally when a new issue is out, or when we have something important or interesting to say. We have no interest in selling your email address.
We use Patreon. They store all your payment info.
We use Thirty Bees for our store. Payment info is processed through Stripe. We don't store your credit card info.