ISU student season tickets for basketball cost about $125 for 15 games, even if you completely discount the fact that amount also purchases student tickets for gymanastics, wrestling, volleyball, and women's basketball; as well as Cyclone Alley membership (and a t-shirt) and Student Alumni Association membership on top of that. While the tickets are indeed oversold (not twice as many, only about 40% more) the student section has exceeded 50% capacity only twice this year so far.
3500 student ticket slots x $125 package price divided by 2500 actual student seats divided by 15 games = $11.66 per seat, per game. Even oversold. Even ignoring everything else the $125 price gets you. Those seats are worth a hell of a lot more than that to any potential walk-up consumer of Cyclone basketball. Possibly triple that much.
Students get a hell of a deal and don't utilize it. If there is routinely 1000-1500 student seats being unused, it is hard to justify continuing the practice, when selling them for $36 would net the athletic department anywhere from $350K - $450K more income over the course of the season.