Advocates of the GNU General Public License (GNU GPL) like to perpetuate the idea that programs released under it are "free as in speech, not free as in beer."  The implication is that GPL’ed software is not necessarily free from cost, and therefore you can in fact license your programs under the GPL and still sell them for money.

Quoting The GNU GPL FAQ:

Does the GPL allow me to sell copies of the program for money?

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.

Quoting The GNU GPL FAQ:

If I use a piece of software that has been obtained under the GNU GPL, am I allowed to modify the original code into a new program, then distribute and sell that new program commercially?

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.

These requirements are the condition for including the GPL-covered code you received in a program of your own.

But those answers are farcical.  The truth is that any "commercial" product released under the GPL will not succeed commercially, because the GPL allows anyone who buys the software to turn around and give it away for free.

I recently sent the following message to the GNU’s contact address:

Quoting my message to GNU:

I’m looking to integrate a pop-up menu system into a program of mine for a new feature that I want to add.  I found a GPL’ed project that implements such a menu system and I’d like to integrate it into my commercial product.

I’ve read the GPL and the GPL FAQ but I’m still not clear about exactly what my obligations would be under the GPL.

Specifically, I charge a fee for my program.  The program is a Perl-based CGI script, so anyone who buys it automatically has the source code.  Still, I do not give it away for free; I sell the program (i.e. the source code) for a fee.  If I include this GPL’ed menu system into my application, then:

1. Can I still charge a fee for my application?

2. Does the GPL give my customers the right to give away my application for free, after they buy it from me, simply because a small part of my application is based on a GPL’ed project?

And the reply:

Quoting GNU’s reply:

> 1. Can I still charge a fee for my application?

Yes.  See [FAQ item] and ["selling" article].

> 2. Does the GPL give my customers the right to give
> away my application for free, after they buy it from
> me, simply because a small part of my application is
> based on a GPL’ed project?

Yes.  When you use that GPLed code, you must release your own work under the GPL as well; this is required by section 2(b) of the license.  As a result, when your customers receive it from you, they’ll have the right to distribute it however they wish; this is permitted in section 1.

I have no problem with the GPL; much of the software I use on a daily basis is GPL’ed software and I’m glad that I was able to obtain this software for free (free as in beer).  But the wording of both the license and the FAQ is misleading, and the suggestion that you can GPL your commercial software is disingenuous.