Anybody can open an AWS account for free.
Yup, lol.
I guess the reason he's selling them is because they require the credit card when signing up. That's something a lot of people don't have multiple of, so I guess it's targeted at those people.
Opening an AWS account requires a phone number and a bank card. Even children under 15 have their phone numbers and bank accounts (and thus bank cards) nowadays, it's absolutely common and normal. Furthermore, using an account that was created in somebody else's name violates AWS Terms of Service and on top of that may be classified as a criminal offense of fraud. So if this kid is targeting anyone he is targeting and abetting criminals. This forum is not for criminals, nor it endorses any criminal activity.