Dystopian book

I read a book back when I was in college about a teenage girl living in a dystopian world. The book would have been published in 2006 or earlier since that is when I took the class. I only remember pieces of the book. I know that the girl lived with her family in a community and she had to venture out of the community ( or her family was forced out ) to the rough area ( where there was a market ) to either buy or sell something. Any ideas. I have been look for this book for awhile. I want to say it takes places in Chicago but I could be wrong.