Hi isralegd,
Welcome to the Mattress Forum! 
Quality Sleep Shop is one of the members of this site which means I believe they compete well with the best in the industry in terms of quality and value. They would be my priority anywhere within about an hour of Chicago. They make mattresses in every budget range and they have offerings within your $700 price range.
The Beloit Mattress Company is also located within 100 miles or so of your area and they are also members of the site and may be worth considering.
Subject to first confirming that any retailer or manufacturer on the list that you wish to visit is completely transparent (see this article ) and to making sure that any mattress you are considering meets the quality/value guidelines here … there is a list of some other retailers in the Chicago area here.
Phoenix