here's a few. im not sure what date u needed but these are ballpark prices from expedia
think of it this way.. u kinda dont wanna pay that much for a hotel since ur only gonna be in there just to sleep right?

Red Roof Inn Chicago Downtown Lowest avg rate $120.00
Howard Johnson Downtown Lowest avg rate $145.67
The Tremont Chicago Lowest avg rate $150.19
Inn of Chicago - Magnificent Mile Lowest avg rate $189.93
Travelodge Hotel Downtown Lowest avg rate $129.00
Congress Plaza Hotel Lowest avg rate $169.00