Hi,

In the classifieds in my city there are one of each of the above mattresses with box springs being sold between $300 and $400.

I don't know much about beds and i'd like to know which is best. They are all apparently fairly new.

I guess I like a fairly firm mattress but overall comfort is maybe more important. Again, the mattresses are all similar in price. What's the best one? and best deal? Could I get a little info on each?

Much appreciated. Thank you.

Byron. Montreal.

Actually apparently the Serta bamboo thrive is brand new in plastic, no box spring and apparently has no defects.  How is it so cheap then? It seems too good to be true. Does anyone know how Mattress sellers work and where they get their mattresses?

Not sure about the Bamboo, but often if you call someone and let them talk, you'll get the whole story. 
My bet is that the others are being sold because they are pillowtops and they have body indentations, even tho they are nearly new.  Such is the way of beds.
You should be able to research each bed online separately. 
If you get one of the pillowtops, choose which one has the springs you like the feel of because you will probably be doing mattress surgery on it.  Oh, and check out bedbugs.  They are apparently a problem these days and you sure don't want those things in your bed!!!
Kait

Don't buy anything with a pillowtop unless the pillowtop is latex (unlikely that it would be).