On the secondary market they are expensive. I think I paid 250 per ticket or something like that in 2022 (through vivid seats (bad experience with them) for the game in Bozeman because all seats were pretty much sold out months in advance.
I have the full radio recording of the 2005 Stanford game digitally. It was from back in the day when you could get CDs from the third party who provided the service. If anyone would like the recordings DM me.