Barbecana offers Schedule Inspector free to universities and bona fide not-for-profit academic institutions in a restricted version.
The restricted software may be installed on any number of computers but will not operate on projects with external sub-projects or with more than 100 tasks. Technical support is available at the same price as for regular users, namely $125 per year, and is recommended but not required.
There is no longer a special version of the software for academic use. Just download the regular version and actuate it. (This will give you a 30-day free trial of the unrestricted software.) When the time comes to register, dismiss the registration dialog using the red cross at the top right. This will close down Project, but when you re-enter Project Schedule Inspector will operate in the restricted mode described above. (If you should subsequently decide to purchase a full license, you can do so by selecting “Register Schedule Inspector” from the Schedule Inspector menu.)