Tidal sprint code seems to be dead. My guess is that the deal for for sprint users, and the internet found out about it and used it too much. Possible Sprint paid for a certain number of codes and they got used up.
Note, they do have a 50% discount for students (Tidal.com, Try Now, Student Discount)
Note, they do have a 50% discount for students (Tidal.com, Try Now, Student Discount)