[bdw5204]

> Want to create something, offer it for free, and know that nobody will modify your code and start selling it? GPL.

You can modify somebody's GPLed code and start selling it. The only restriction is that you must offer to share your source code with your customers and give them all of the same rights you have under GPL.

There is also a loophole that lets you sell modified GPLed code without sharing the source or giving them your GPL rights: run it on a server. AGPL closes this loophole which is why it is unpopular with large tech companies.

Any license that prohibits selling modified versions of somebody else's code would, if it became popular or was adopted by a popular project, be denounced by both FSF and OSI for violating the principles of the FOSS movement because the right to sell other people's FOSS software is considered an important user freedom. Writing such a license involves making fairly trivial changes to MIT or BSD but does make it impossible to combine any code licensed under it with GPLed code.