Seen some mentions of Recurly and Chargebee and Sentry did something in 4 weeks of engineering work and 10k LOC. With that said, are there any open source solu

Seen some mentions of Recurly and Chargebee and Sentry did something in 4 weeks of engineering work and 10k LOC. With that said, are there any open source solutions that come close to not needing a 3rd party? I say close, as covering the loss with development time is not a problem in my case. Unfortunately, I am not able to use Stripe. Thanks!