[happyvalley]

Happy user at mailbox.org

They are hosted in Germany, have a strong stance re data protection, and have a very cheap basic plan. Plus multiple payment options, I think you can even send them money by post for complete anonymity.

Edit: You can use a custom domain

[craftyguy]

I like their inbox encryption feature, all inbound mail is automatically encrypted with your gpg key. This means that mails downloaded to clients must be decrypted with your gpg key, and it's impossible to read mails in your inbox with their webmail thing. This means that if your device is stolen, your emails (their contents) are still encrypted.

[matogato]

Another happy user at mailbox.org here!

Mail (with optional custom domain), calendar, address book, storage and XMPP for 1€/month.