Regarding mattresses, I got a new one a few years back, and after exhaustive searching, I found this place
Foam Factory.
They sell all kinds of foam for all kinds of applications
and their prices are very reasonable.
I was particularly interested in a memory foam mattress. They will build a mattress any way you want it, with any kind of foam you want, and they list the various foams in engineering terms (under "RESOURCES"), which I found to be particularly helpful.
I got the 5 pound foam bed which proved to be a bit firm, but I have "civilized" it with a more yielding topper.
My gal got the 4 pound, with the memory foam layer being 4", which made a very nice bed.
But it all depends on your body mass.
They offer a "terry cloth cover" which I would advise to everyone.
* I must warn that a temperature sensitive foam bed in an unheated bedroom can become extremely firm until it's warmed up. *
A winter-time heated mattress pad on a timer makes it just wonderful.
Best,
-AC_Hacker