Free Software/Open Source code is by definition Free, but writing it requires heavy competencies. There are many ways (Business Models) to finance these developments. Some of them include mixing Open Source code with Proprietary code. Regularly developers that started with Open Source, move to proprietary or Open Core business models. Based on 10 years of experience in producing Open Source Code with the company XWiki SAS, and on analysis on how other companies have evolved their business models and how it impacted their open source contributions, this talk proposes to review these methods in the light of the sustainable financing of Open Source Code: in which ways can one write FLOSS code for the long term. What are good practices from all participants to the FLOSS eco-system which can lead to more Open Source code production and better Open Source products.