Hi bwilliams1848,
This article may help you eliminate most of the worse choices and help you focus on the better ones.
Unfortunately you are in somewhat of a no mans land when it comes to local manufacturers that are close to you. There is one however in Verona and after that the closest ones are all over 100 miles away in several directions …
http://www.capitalbeddingonline.com/ Local factory direct in Verona, MS. They make a range of innerspring and memory foam mattresses and a latex hybrid. I haven’t talked with them so I don’t know the specifics of their mattresses but they fit the profile of smaller local manufacturers who have been in business for a long time (over 40 years) that make better quality and value mattresses.
Post #57 here includes a manufacturer in Birmingham that I think highly of.
Post #2 here includes two manufacturers in Memphis and one in Meridian, MS and includes some other options in the Jackson, MS and Memphis, TN areas as well.
Some of the better local possibilities (and the brands they carry which I would investigate as possible sources of better value) include …
http://www.kirkseybrothers.com/ Tupelo, MS. Jamison, Englander.
http://www.roomtoroom.net/ Tupelo, MS. Jamison
http://www.smithfurnitureappliance.com/ Fulton, MS. Jamison, Symbol
These will all need some initial phone calls along the lines of this article to make sure they are willing and able to give you the specs of any mattresses you test and like (especially including foam density in the case of memory foam or polyfoam) and to get a sense of their overall level of service and knowledge. If they are able to give you the information you need to make meaningful comparisons and seem to have good knowledge about mattress materials and are happy to give you some initial information on the phone, then I would pay them a visit.
Other than a longer drive or some research into possible better value locally, you may also want to consider an online purchase if the quality and value with some of the manufacturers listed in post #21 here compared to what is available locally here justifies the additional risk of an online purchase.
Phoenix