These guys are one of the most popular in St. Louis for sunrooms. Their showroom is kind of far out for most St. Louis city and county residents, but it's worth the drive as they have a lot to offer in designs and styles. They have a variety of sunrooms that will fit your budget and your space needs.
Very nice staff as well. I highly recommend that you take the time to shop here if you are in the market for a sunroom in your house.