Hi liquidfina,
A mattress is meant to perform specific functions and is much more than just a commodity where the value can be measured in terms of cost per inch of foam or per pound of fabric so there is really no such thing as a mattress that is the “best bang for the buck” for any specific person because each person can have very different criteria and definitions of “value”. Outside of how well a mattress “matches” your specific needs and preferences in terms of PPP … a mattress is only as good in terms of durability as the quality of the materials inside it regardless of the name of the manufacturer and I would avoid “brand shopping” (see post #5 here).
The “value” of a mattress purchase for any particular person always depends on all the criteria that are most important to them (see post #13 here) and on how a mattress compares to your other finalists. A mattress that is “good value” for one person many not be good value at all for the next depending on the parts of their personal value equation that are most important to them.
There is also more about safe, natural, organic, and green mattresses in post #2 here and the posts it links to that can help you decide on which materials you are most comfortable with having inside your mattress.
The better options and possibilities I’m aware of in the Toronto area are listed in post #1 here.
Phoenix