Hilton ORD is super cheap on Hotwire as an “opaque” booking that can be easily unmasked using the TripAdvisor info. It’s very conveniently located for the CTA blue line.
Ironically, between the carpeting in the hotel and its location at the airport itself, there are times when those transit passengers with lots of wheeled belongings in tow may actually be better off using a hotel shuttle bus to get to a different ORD area hotel than staying at the Hilton ORD.