This year single game tickets at NDSU look like they are about $65/sideline and $55/end zone other than. St. Thomas (reduced).
I'm guessing tickets for NDSU/UND or NDSU/SDSU in the dome would be a premium? I've always just went with my dad so not sure. I would guess the price is similar +/- $10-15.
Maybe the premium on this game is a bit steep (or isnt) but there is no reason UND should ignore the substantially higher demand. I think they probably priced it out pretty well by looking at the seat map.
EDIT: you do want the butts in seats. It's tough to do that these days at most schools. But 95% of the time, the issue isnt the price there. Its lack of interest.