It's tempting. Put some ads on your blog, a donation button on the project page, get a low paid student job, etc. It's fine, if you can work on free software, right? Some money is better than nothing, isn't it?
No, it isn't. Because it interferes with other ways of being compensated for free software development, such as reputation, control, freedom, learning, or just satisfying your curiosity. Money adds dynamics which can go against these. It changes to whom you are accountable, it alters expectations, and it can actually harm your motivation, because money is a bad motivator. So you need to be very careful when putting money into the equation.
That doesn't mean that there are no good ways to get paid money for free software development. In fact an increasing number of companies have realized that they are better off developing a good part of their software as free software, and they don't compromise on quality or payment. So there are well-paid jobs for free software developers. Guess who gets these jobs. Not those who do it for cheap, but those who have built up a good reputation as a free software developer.
Contributing to free software actually is a great way to build up a career. You are in control. You don't need a university or company program, you can start any time. You can build a reputation doing something you want, something that matters. You can learn and grow following your passion. This is a great foundation for a professional career, and studies show that committers to free software actually get higher salaries than those who don't do this.
Your work on free software is an investment in your happiness, your career, and a better world. Don't sell it cheap.
