Hi moocoop,
Congratulations on your new mattress :). You are certainly making a great quality/value choice and I’m looking forward to your comments and feedback once you’ve received it and have had the chance to try it out.
There is also more about the many variables that can be involved in how any manufacturer or retailer prices their mattresses in post #14 here but of course there is no real answer to this because the internal financials that show how a manufacturer calculates their prices are proprietary and this isn’t information that a manufacturer would share with the public so from a consumer perspective it’s really a matter of knowing how to make meaningful comparisons between mattresses based on the materials inside them and all the other criteria that are most important to you (one of which is price of course).
Having said that … while polyfoam is a relatively low cost material relative to other types of specialty foam like memory foam and polyfoam … I also think that their pricing is very “aggressive” and would probably involve lower margins than other similar mattresses.
I’m glad you found the reference post about foundations and support systems.
Just to recap for the benefit of others that may read this … any mattress with a polyfoam support core (which includes most memory foam mattresses) will generally do best with a firm, flat, and evenly supportive support surface underneath it that has minimal to no flex under the mattress and for larger sizes with at least one center support beam that has good support to the floor to prevent any sagging in the middle of the mattress. The components (bedframe and foundation or platform bed) need to be strong and durable enough to support the weight of the mattress and the people sleeping on it without some of the parts bending, sagging, shifting, or breaking with extended use. The support surface under the mattress (which may be slats or a steel or wire grid) should have enough surface area to prevent the mattress from sagging through any gaps or spaces in the support surface over time but still allow some airflow under the mattress. If a foundation has a slatted surface then I would suggest that the gaps between any slats are no more than about 5" (with 1 x 3 slats) although less than 4" would be better yet.
Phoenix