The average cost of domestic draft in a keg beer is between 55 and 75 cents per pint (16 oz).
A 32 oz plastic cup costs about 15 cents.
So... for a 32 oz beer, the Cajundome's cost is somewhere between $1.25 and $1.65 per beer (and that is being very generous, it's probably cheaper because of the volume they purchase).
$1.25 cost selling for $10 is a 700% markup.
$1.65 cost selling for $10 is a 506% markup.
Obviously, paying the employees who serve the beer is not factored into these numbers.
With that said... I still pay the $10, but I know others who refuse to pay $10. I also know people who used to purchase 2-3 beers a game, but now limit themselves to only one beer.