A while ago I was contacted by a friend who asked me if I am offering a commercial version of Rhino Mocks.
That is not a mistake, he was working in a place where the use of Open Source Software was not allowed, and decided that the simplest way to use the tool was to go through the normal route, buy it.
I wholeheartedly support this decision. :-)
Considering how hard it is to make some organizations use Open Source projects, and how used those same organizations to buying software, it is probably the right decision. It make things much simpler, and you are actually supporting OSS along the way.
At any rate, if you find yourself in the same position, you can just go and buy Rhino Mocks.
The retail version and the OSS version are… well, look at the title, then figure it out.