Buy USC ticket outside the stadium?

[RazorRunner]

Guys, I've been reading Hogville daily for a long time but just recently joined, this is my first post.  I'm going to be in LA on 9/17 and plan to be at the game.  Not sure if any of the $40 tickets are still available thru UA but I really don't want to be that far from the action anyway.  Does anybody have an idea of what a ticket located say between the 20 yard lines would go for outside the stadium on gameday?  I have no clue whether we're talking $100 or $500 or what? 

Also, what's the best strategy for dealing with the street ticket vendors?  Maybe wait till just before kickoff (then chance being left out in the cold)?  I need only 1 ticket which might be a disadvantage.