How about some cheap slip-in presentation folders from a local art supply store? I'm guessing that cost is a concern, so you don't have to display everything at once - you could rotate photos through over a period of time. An example of what I mean is here:
https://www.bhphotovideo.com/c/prod...lders_wsi810p_white_slip_in_photo_folder.html
The "right way" to do it would be somewhat similar, behind some sort of "conservation matt," which is a high quality material vs cheap paper which would probably damage the prints over a long period of time. You might talk to your art department - they are likely familiar with this sort of thing.
If you want some serious info on "proper" display methods for long term use, probably way more info than you want, you can download a couple of chapters from Henry Wilhelm's book - maybe just chapter 12:
Dead Link Removed
Personally, I'd probably just look for cheap slip-in folders on sale somewhere local and do a rotating display. If you think any of the students may be saving these long-term, they should get the prints out of the (cheap) folder; high-quality stuff is available at higher cost.