"there must be a well-publicized means of obtaining the source code for no more than a reasonable _reproduction_ cost, preferably downloading via the Internet without charge"
The software itself MUST be free, and the _reproduction_ costs reasonable.
You cannot add clauses that make me pay money or restrict my use. It must be free as in beer to use and redistribute either modified or in its original form.
When you pay for a copy you don't buy rights to use the open source software, you already had them. You buy the paper it's printed on.
And you can't deliberately make it hard for me to compile either.
Arguably nagware is that.
If you own _all_ the rights you can also release a version for cash, but if you then tell people that you are selling them open source software, and you sell them a version for which the source code is not freely available you are breaking the law/rules.
The quote you have put there says nothing about binaries, only the source code. And indeed the source code has essentially no reproduction cost since it's downloadable via the Internet without charge as it's preferred.
>you sell them a version for which the source code is not freely available
But the source code IS freely available. All the nagware/restrictions/whatever is in there as a build option. Play Store builds have them enabled unless you buy a license, F-Droid & GitHub builds have them disabled.
In any case it seems you're mistaken about what free software exactly entails, and what is and is not allowed by GPL. For a TL;DR refer to the ones behind it.
>You are allowed to sell copies of the modified program commercially, but only under the terms of the GNU GPL. Thus, for instance, you must make the source code available to the users of the program as described in the GPL, and they must be allowed to redistribute and modify it as described in the GPL.
Nope.
> Open Source means something, not just that the source code is available.
That the source is openly licensed. Providing paid version is a different thing.