How to vet users who apply for discounted subscription license for education

Does anyone know a method for vetting users when people apply for discounted educational licensing with a discount?

So far I have looked at:

• providing a license manually on per user basis when user can submit a valid student card - problem here is potentially creating a heavy workload for our rather small CS team
• another option is to programatically only allow to subscribe for educational license if users email has .edu domain

Each one of the above has obvious patterns for abusing the system, was wondering if anyone has previous experience with setting up a similar system and how you were able to resolve it.