So many people have gotten the ideas of Free Software confused with commerce. It is a commonly held belief that software released until the GPL cannot be sold. First off, there is nothing in the GPL license that talks about selling. And more importantly I think few authors of GPL software would want to prohibit people selling the software that they write. I am here to say quite directly: please sell the GPL software that I write! Please take it, use it, improve it, make a profit on it! All I ask are the terms that are in the GPL: that you contribute you distribute the source code and you contribute back improvements to me so I can include them.

While I happily accept payment for working on software, I also feel it is important that people are not required to hire me to work on the software that I wrote. If someone wants to pay someone to make improvements to Firmata, I will happily take on the job. But if someone is better situated to do the work, then hire them instead. For example, a competent person who can work in the same room as you is worth more than the expert you have to talk to via email.