Depends on what you define early September, as first half of the month there is a huge convention going on in Chicago, Print13 expect to have 50,000 attendees (Sept 8-12), and a smaller one Canon expect to have 5500 attendees (Sept 10-12).
So with 55,500+ visitors basically from Sept 6-13 expect to see even a Hampton Inn would cost $200+ a night.
Also, being one of the hotel chain member doesn't give you a good rate for its members, it is for you to collect point and/or miles, gain status, as anyone can join for free.
Originally Posted by
ILuvParis
The Langham just opened in the former IBM Building, across the street from the Trump. It looks like it will compete with Trump, Peninsula, Four Seasons and the Waldorf Astoria. No idea about the rates, but being brand new, perhaps you can get a deal.
http://chicago.langhamhotels.com/
Those are constantly $350+ even for low season, adding all the taxes expect $400+ a night.