Does the GPL allow me to sell copies of the program for money?(#DoesTheGPLAllowMoney)
Yes, the GPL allows everyone to do this. The
right to sell copies is part of the definition of free software. Except in one special situation, there is no limit on what price you can charge. (The one exception is the required written offer to provide source code that must accompany binary-only release.)
Does the GPL allow me to charge a fee for downloading the program from my site?
Yes. You can charge any fee you wish for distributing a copy of the program. If you distribute binaries by download, you must provide “equivalent access” to download the source—therefore, the fee to download source may not be greater than the fee to download the binary.
Does the GPL allow me to require that anyone who receives the software must pay me a fee and/or notify me?
(#DoesTheGPLAllowRequireFee)
No. In fact, a requirement like that would make the program non-free. If people have to pay when they get a copy of a program, or if they have to notify anyone in particular, then the program is not free. See the
definition of free software.
The GPL is a free software license, and therefore it permits people to use and even redistribute the software without being required to pay anyone a fee for doing so.
