Just a few days ago, ESPN F1 reported that the Circuit of the Americas was considering more grandstands between turns 9 and 10 and turns 10 and 11 "in place of other types of seating that had been planned for those areas." Now it's done: grandstands have been added at those two spots adding space for 15,000 more butts come race weekend.
What'll it run you? A search on Ticketmaster for one ticket yielded a grandstand seat at Turn 9 for $315.24 for the three-day weekend, plus shipping and any fees. If that's too rich, General Admission tickets for $171.99, inclusive of fees, are still in stock.