Hi rd3482,
Post #14 here has more about the many reasons for price differences between two manufacturers or retailers which includes the cost of the raw materials (including the type and blend and amount of latex, the cover and quilting, and all the other materials and components in each mattress that can affect the cost), the cost of manufacturing, return and exchange policies that are built into the cost, and all the other factors that lead to the final cost of a mattress and how they may differ between two businesses.
While the “raw material cost” of a mattress can be an important consideration if you are comparing two mattresses that are the same in all the other ways that are that are important … the value of a mattress also involves much more than its raw material cost. There is more in post #13 here about the most important parts of the “value” of a mattress purchase.
Phoenix