Read. On Windows, Mac, and mobile devices, you can make a decent living selling software directly to hod. Things are different for open source software. Selling applications, physical products, and online services is also how the big guys make their money. Apple and Microsoft want you to use their programs on their machines. Google differs in that it makes most of its money from ads, but Canonical took a beating when it tried something even vaguely similar. In short, you need to take a different approach to making money in the open source world.