Ask HN: Which SaaS for simple plain-text newsletters?

I have ~200 subscribers and I want to send plain-text newsletters to them. No link/open-email tracking, no advanced features. Back to basics. I want to pay at most 5$/m for this.

Also, I'd like a trivially simple approach to sending a newsletter. Ideally, just send the main body of a newsletter to a dedicated email. A newsletter service would listen on this address, fill in my predefined email template with this body and send it to the subscribers.

I'm looking at MailChimp, Grip, SendGrid, but they are either expensive, cumbersome to use or doesn't support my use-case with free tiers.

Please tell me that something like this exists.