You can do anything with GPL:ed code—including selling products based on it—but you have to share the source code.
“Using the GNU GPL will require that all the released improved versions be free software. This means you can avoid the risk of having to compete with a proprietary modified version of your own work.” ** ref **
You can not remove the author’s copyright or change the code’s license to be more restrictive or permissive. You can not take a GPL’d app and rebrand it to charge a license fee. You could do that if code was CC… That was the original question
The author of GPL’d code might sell a version under a different license.
Using LGPL code is more practical if your looking to do a commercial app.
(There are also a number of other licenses that permit commercial use)
I mentioned Webber in my prior post… Initial post mentioned as being GPL’d… it isn’t
From what I have seen, Webber appears to be a well designed commercial product.
What modules Webber offers for “Free” have at their core ... GPL’d code.
That is why people use GNU GPL