i wouldn't mind paying $20-30 to cover facility fees, but $100+ is just gouging. there is no way it costs that much to operate the facility for one day. where is this extra money going? $100 x 100000 people (at least*) = $10,000,000.
the UK show will not be free either:
ALL TICKETS FOR LONDON WILL BE PRICED AT £55 EACH (about $110 USD)
* football capacity is 80k in the stands, i'm sure they'll fit at least 20k on the field.
EDIT: furthermore, the article mentioned "A lot of cities were competing to get this show, and the state of New Jersey and the city of New York opened up their arms and said to come here." = sponsorship, tax breaks, incentives, etc...