I'm developing an educational game that I want to sell the game on Steam and Itch.io, but I also want to provide it for free to educators. 

I'm thinking the easiest way to do that would be to get them to email me with verification, and then provide them with a single Itch.io key which they can use to install on as many computers as they requested. Would this fall within the Itch terms of use? Would there be a better way?

For anyone interested, I sent an email to Itch support and this is what they said: "This is not against our terms of use. This is a great use-case for our key generation system. Tell us if you have any issues."

Hello. You must at least lunch the game, talk about it, give details, and then try to sell it. You have to convince them to buy it from you.