That's the price for the worst seats in the stadium though.
Prices here are usually based a bit off the quality of the team and therefore the desire for tickets. You'd probably see the absolute worst seats costing $40-$50 at the NFL on a single game price, so maybe $30-$35 for a season ticket holder. $240 is probably the absolute minimum you could pay here (for the Dallas Cowboys, it looks like it's like $590 for the cheapest ticket and that doesn't include $60 per game to park) but again, that's for less than half the games played.
That being said, here are the prices for a nearby MLS team who just opened a new stadium (20 games). The Supporters' Section is standing room only I believe.