Final-Four universities are obliged to buy 400 hotel rooms, spend $32,000 on a party in a local convention hall, and much more. They also only get to buy a small number of tickets, so they end up having to pay top dollar to see the games.
The University of Texas lost $130,000 on their last Final Four appearance. On the bright side, it's possible that they might make it up later through merchandise and such.
Once again: Why do educational institutions have sports programs?