Not sure if it's been requested before so if it has then oh well!
My suggestion/request is a simple one in my opinion and I'm fairly surprised something like this doesn't exist in WHMCS already.
First part is:
A system for students to verify their Education email addresses and then tie this into products/services that are being marketed and sold to students. They pay until they're no longer in education or if they change their email address their service is temporarily suspended and the student discount is removed
Second part is:
A system for teachers/tutors to create an account and to start creating students their own Sub accounts. (With the above implemented for if they change their email address) And for the ability to charge per student account created.
I've already spoken to a few people regarding this and I feel like it'd be a good thing to implement into WHMCS at some point since not all educational establishments have internal systems to run web servers or anything similar for students.