I would like to sell a Python application that uses PyQt4. The commercial licenses for Qt PyQt cost thousands of Euros together. Do I need to buy a commercial license?
Consider this from a "packaged" point of view where I'm providing an Ubuntu package through the Software Center. My package would "depend" on existing Ubuntu Python and PyQt packages so would I need to license something that Ubuntu is redistributing, that I am not directly?
Conversely, if I did include a GPL/LGPL Python library in my package would my package be able to remain non-free? Couldn't I just make the source to the GPL libraries available (if modified)?
If the answer is "You need a commercial license", are there any cheaper alternatives you know of (like royalty-based payments instead of up-front developer fees)?