Najafi Q&A: Authorization

There is an educational academy selling electronic courses for a fee, and this academy stipulates that if the monthly income of the buying person is (300) dollars or more, the price of the course will be (150) dollars, and if the monthly income of the buyer is less than (300) dollars, the price of the course will be ( 45) dollars. Here, I have (3) questions: 1-If there is a person whose monthly income is less than (300) dollars, can he appoint me to purchase this course for him or not? 2-If this person bought the course, can he sell this course to someone whose income is more than (300) dollars or not, knowing that the academy mentioned that all rights reserved? 3-In one of the course introductory videos, several points were mentioned, among which is that benefiting from the course is limited to the first-degree family only. Is this condition obligatory to adhere to or not?