[cjbprime]

I don't consider this to be open source software. Most straightforwardly, because it fails to meet section 6 of the open source definition:

http://opensource.org/osd

And practically, because open source is a model of collaboration, and there's no collaboration here -- django's a collaborative software project, and this is an engineering dead end where you pay (or not) for the code and then it gets thrown away afterwards. It's the wasted effort and duplication that bothers me, not the fact that money is involved.

[DanBC]

How can they release it under a CC BY-NC and also charge for commercial use? What licence are the paid for versions under?

[cjbprime]

The paid-for version could be a standard Microsoft-style proprietary software license -- "you are licensing this software from us, you have no rights", etc.