I grant free licenses to students for academic work, however I need to draw an income from the development work (which I'm pretty much full time on). I offer a free month to commercial firms for evaluating the tools, and if they proove to be useful, there are commercial licensing options availalble.
When you've installed, run the rhino command sdrZZLicenseRequest and follow the prompts, I'm happy to assist with getting started if you encounter any problems.