Hi RazzleDazzle,
Subject to first confirming that any retailer or manufacturer on the list you wish to deal with is completely transparent (see this article) and to making sure that any mattress you are considering meets your specific criteria and the quality/value guidelines here … the better options or possibilities I’m aware of in and around the Lansing, MI area are listed in post #2 here.
The list for the Grand Rapids/Holland area is in post #273 here.
Phoenix