Memberful.com also integrates natively with Stripe and Discourse and is what I previously used. They charge ~$25/mo plus 4.9% on top of Stripe’s 2.9%.
EDIT: I’m moving to free access to the site, then allowing someone to upgrade via Gravity Forms on Wordpress with Stripe, which then creates a new WP user, which is SSO for Discourse and updates Group access to view “protected” groups. It’s not super straight forward (like Memberful is), but it’ll save me 4.9% which is a lot. Here’s my flow: Wordpress SSO flow