At least under section 6 of the GNU GPL, there are limits on how much one can charge for the work.
If the object is offered in physical medium, the profit margin can only be imposed upon that, not in the costs of conveying the complete and corresponding source. There are cases where such conveying must also be done without charge. See: http://www.gnu.org/licenses/gpl-3.0.html#section6
signature.asc
Description: This is a digitally signed message part
