Once you find a person ( or two ) who has bought a used car recently, get them to tell you what has happened. Did they feel like they got a deal ? Most people forget that the word "deal" is in the word "dealer" and is for the buyer, not the seller. Did anything break on their car ? If so, how was it handled ? There are a lot of questions to ask, and it is all for your benefit. One of the best questions to ask is; "What is your overall feeling about your purchase ?". If it is is positive, it is likely you will also have the same experience.
Car dealers in Chicago or whatever city are there to make a buck. If they are also concerned for their reputation, they will have many of their happy customers showing this. Look for the car dealer's name on a logo or perhaps a license plate holder of used cars in Chicago. Your best deal will be finding the car you want at the lowest price possible without a lot of extra expenses for upkeep. Once you know what you want, keep your eyes open for those signs of an agreeable purchase from past used car customers.