If you plan on parking your car at O'Hare International Airport for an extended period of time, then the Economy Lots are the best option. The daily rates range between $15 and $22 per day
Some hotels in Rosemont offer parking like Loews hotel. They offer shuttle services (about 10 minutes to the airport) that are free. Don't be cheap not to tip the drivers. There are also parking places in Mannheim i.e preflight, blue sky, etc.
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