They don’t advertise it, just message support from your .edu email and tell them your username. They’ll apply it and let you use the STUDENT promo code. It’s 50% off the year plan so $5 a month.

Basically 3 good choices

ProtonVPN AirVPN IVPN

Proton has a 50% off student discount bringing the price down to $5 a month for all proton services.

IVPN is probably the best but most expensive.