Well Amazon web services are the most used web hosting and clouding in the internet they have many different services as web host, vps and storage
Also they offer coupons to purchase a subscription in any service instead of using you money some people are selling these coupons for example 100$ coupon you will get it with 15$ instead of paying all the 100$. I'm not sure how they get all these codes and coupons but i think it's related with education email.
But i know that the purpose is to save money and use aws for lowest price.