Right. Copyleft licenses (the GPL and the like) only require you keep software free as in freedom, not as in beer. You can sell the software just fine, so long

Right. Copyleft licenses (the GPL and the like) only require you keep software free as in freedom, not as in beer. You can sell the software just fine, so long as you provide the source. And non-copyleft licenses let you do whatever you want. You can take non-copyleft open-source software, add your proprietary junk and sell it at a killing, if you want. You don't even have to provide the source.