Hi BRZ,
Welcome to the Mattress Forum! 
I’m glad you found us, and thank you for the kind words. And thank you also for taking the time to follow the steps in the Mattress Shopping Tutorial as you go through your decision making process. B)
You’ve already read about the Ikea and Bob’s mattresses, so you already have a “leg up” on what to look for and questions to ask. At the point of being redundant, I would avoid any product that contains lower-quality materials or when you can’t confirm the type/quality of materials within a particular product.
You’ve also done your homework and found out about the retailers in the Chicago area. Based upon your post, you may wish to phone some of these stores beforehand, as they are a bit of a distance form your home, and tell them what you’re looking to purchase to see if they have anything in your quality/budget range.
In case there are no better quality and/or value choices available … then I would look online and use the experience and expertise of the members listed in post #21 here who are all very experienced and knowledgeable and specialize in providing the type of help and guidance on the phone that can help you make good choices. There are a wide range of latex and memory foam and other options included in the choices there and I believe that all of them compete well with the best in the industry in terms of their quality, value, service, and transparency. Their detailed knowledge of their mattresses and how they fit with different body types and sleeping positions along with your feedback from local testing, a customer base of many people that they can use as reference points, and any exchange, return, or any options they have available to customize a mattress after a purchase can help lower the risk of an online purchase. These online retailers or manufacturers can also be a good “value reference” for local purchases to make sure that if you are paying a “premium” for a local purchase (in exchange for the kind of “in person” guidance, service, and value that comes with dealing with a local retailer that can help you make more “accurate” choices that you have tested in person) is not too high. Post #2 here and this topic have more about the pros and cons of a local vs an online purchase.
In addition to the online members of the site listed in the previous membership link … post #12 here has some of the better online memory foam options for those who are looking for a memory foam mattress.
As you stated that you wanted to stick to a more basic budget range, then post #4 here and the posts it links to also include many of the better lower budget online options I’m aware of as well.
I hope that information is helpful to you. I look forward to learning if you find something that works for your personal preferences and your budget range.
Phoenix