The terms of the deal are as follows:

                             Custom       Drupal       Drupal Multi  Developer
Price                        from £49.99  £19.99       £39.99        £9.99
Number of Websites           1            1            unlimited     unlimited
Full PHP Source Code         Y            Y            Y             Y
Access to Support System     Y            Y            Y             Y
Access to Latest Releases    Y            Y            Y             Y           
Example Scripts and Docs     N            N            N             Y          
Access all API Features      N            N            N             Y

No options to get the code without paying, and I am guessing since he is selling single use and multi-use licenses, the code isn't being released under the GPL.

Brian

Antonio P. P. Almeida wrote: 
On 19 Nov 2009 16h47 WET, naheemzaffar@gmail.com wrote:

  
2009/11/19 Alex Barth <alex@developmentseed.org>

    
This may have come up before, but
http://integrationservic.es/drupal.php launched on Nov 12 and
appears to be violating drupal's GPL2 by charging 33 $ for a module
download.

      
The GPL does not say that the module has to be for free. However
once the module has been "distributed" to other individuals, no
additional restrictions above the GPL can be added, so if the person
has clause that the purchasers cannot sell/pass the module onto
others, that would be a problem, otherwise, no it wouldn't.

IANAL, but that is my understanding.
    

Yes it's true. It depends on the terms of the deal they are
offering. IANAL also.

--- appa