I attended Oklahoma in the mid 80's, was in the band so all of my tickets were free. Other students were $25 for a season ticket, no reserved seats. You had to go stand in line outside the ticket office and it was one per person with their own student ID. The line would usually start to form the night before and there would be a party on the sidewalk all night. Ditto for men's basketball. All other sports were free, just show a student ID, no ticket required.
I don't know what they do today, but the student section is quite frequently not full. When it does fill, it's last minute and they leave before the game is over frequently. That doesn't bode well for future donations to the university and athletics, IMO.