Just slap an education discount on it and call it a day. There are plenty of reasons to do that anyway, you want students to get trained on your software and use it in their formative years as much as possible.

Many go even further and just give the product away for free for educational institutions and individual students (Github, Jetbrains and Tableau come to mind as examples)

For a small-scale implementation in a university, open core without SSO is no-go: nobody has any money or purchase authority.