Added sponsoring & contributing info to README

README.md

@@ -352,4 +352,23 @@ $json = json_encode(Price::USD(999, 4)->setVat(6));
 $price = Price::json($json);    // 4 x $9.99 with 6% VAT each
 ```
 
-> 💡 **Nice to know**: you can also use `Price::json()` in order to create a Price object from an associative array, as long as it contains the `base`, `currency`, `units` and `vat` keys.
+> 💡 **Nice to know**: you can also use `Price::json()` in order to create a Price object from an associative array, as long as it contains the `base`, `currency`, `units` and `vat` keys.
+
+---
+
+## 💖 Sponsorships
+
+If you are reliant on this package in your production applications, consider [sponsoring us](https://github.com/sponsors/whitecube)! It is the best way to help us keep doing what we love to do: making great open source software.
+
+## Contributing
+
+Feel free to suggest changes, ask for new features or fix bugs yourself. We're sure there are still a lot of improvements that could be made, and we would be very happy to merge useful pull requests.
+
+Thanks!
+
+## Made with ❤️ for open source
+
+At [Whitecube](https://www.whitecube.be) we use a lot of open source software as part of our daily work.
+So when we have an opportunity to give something back, we're super excited!
+
+We hope you will enjoy this small contribution from us and would love to [hear from you](mailto:[email protected]) if you find it useful in your projects. Follow us on [Twitter](https://twitter.com/whitecube_be) for more updates!