I have an ORD parking pass, but I had to get it through my airline. That is the only way to do it, because ORD parking is on the Airport Operations Area. You need to have a badge to park. If your airline won't do it, then you are out of luck. I am running into that problem now at MDW. I might actually re-bid my base simply because of this commute/parking issue.
I parked at the Doubletree Club hotel on Mannheim Road for a while, and at the time it was $50 a month. The hotel has changed to a different brand, so I'm not sure if they offer it anymore. The hotel was just North of the Allstate Arena. That might be an option!