You custom design, build, and install, information system applications for small businesses using an Open Source operating systems. The other thing you do is take advantage of the superior learning environment. You can make contributions to Open Source however you should sell your designs to prospectors as well, that is sell the designs and then leak them out to the Open Source community over time. You will get paid for what you know. In addition there will be many additional avenues in the future. Above all you must interpret situations and don't be constrained by vendors, you must be original.