I would pay over face value for Slayer, but I doubt you'd have to.  Assuming Slayer come on around 9:15, if you get to the venue at 8:30, scalpers, er ugh, "ticket brokers" will be getting antsy to recoup some of their $$$$ and they will be giving them away.  I always wait until after the 1st quarter of a football game if the price is to high. Tix go way down after the event starts.  Metal concerts are usually cheap anyway.  I got into TON and Misfits one year for 5 bones.  I got into Danzig and Prong for 10.  Living Colour cost me about 7, Cheap Trick was 4 for 10 from a broker last spring.  Nothing to worry about.