It is, after all, open source and we make it all available for free.
However, having great contributions to D have landed several contributors very nice jobs. The sponsors of the annual D conference, past and present, did so to look for crackerjack D programmers. I expect it's the same for other open source conferences.
You can join open source. For example, at dlang.org we don't care how old you are, and we won't pull crappy code.