Add Kill Bill to Money, Budgeting & Management (#3851)

README.md

@@ -1392,6 +1392,7 @@ _Related: [Inventory Management](#inventory-management), [Resource Planning - En
 - [budgetzero](https://github.com/budgetzero/budgetzero) - Free, self-hosted, open-source, envelope-budgeting web and desktop app. ([Demo](https://app.budgetzero.io/budget)) `AGPL-3.0` `Nodejs`
 - [Crater](https://github.com/crater-invoice/crater) - Free & Open Source Invoice App for Freelancers & Small Businesses. ([Demo](https://demo.craterapp.com/)) `AAL` `PHP`
 - [DePay](https://depay.com) - Accept Web3 Payments directly into your wallet. Peer-to-peer, free, self-hosted & open-source. ([Demo](https://depay.com/products/payments), [Source Code](https://github.com/depayfi/widgets)) `MIT` `Nodejs`
+- [Kill Bill](https://killbill.io/) - Open-Source Subscription Billing & Payments Platform. Have access to real-time analytics and financial reports. ([Source Code](https://github.com/killbill/killbill)) `Apache-2.0` `Java/Docker`
 - [Family Accounting Tool](https://github.com/nymanjens/facto) - Web-based finance management tool for partners with partially shared expenses. `Apache-2.0` `Scala`
 - [Fava](https://beancount.github.io/fava/) - Fava is the web frontend of Beancount, a text based double-entry accounting system. ([Demo](https://fava.pythonanywhere.com/example-with-budgets/income_statement/), [Source Code](https://github.com/beancount/fava)) `MIT` `Python`
 - [Firefly III](https://firefly-iii.org/) - Firefly III is a modern financial manager. It helps you to keep track of your money and make budget forecasts. It supports credit cards, has an advanced rule engine and can import data from many banks. ([Demo](https://demo.firefly-iii.org/), [Source Code](https://github.com/firefly-iii/firefly-iii)) `AGPL-3.0` `PHP`