Mattress Forum

I have been lurking for a few weeks and am about ready to pull the trigger on a mattress but I would love some advice. After not being all that thrilled with the inner spring mattresses we have tried but liking the foam ones that are way too much money, we are considering a DIY build to save money. What we were considering was this mattress from Sam's Club for a base: 

http://www.samsclub.com/sams/shop/product.jsp?productId=123666

and then covering it with 3" of soft latex from Foam by Mail, like this:

http://www.foambymail.com/LTX_T/talalay-latex-foam-topper.html

Alternatively, we might zone it a bit with two 2 inch layers, cut for hips, legs, shoulders, etc. I have looked at a few threads on here about putting latex on memory foam, but haven't had any definitive answers. One of the reasons that we want to go with Sam's, though, is if we hate the mattress we can return it, unlike everywhere else but Costco (we're members at Sam's). The mattress we are looking at at Sam's, the Sleep Visco 10" Tight Top Mattress, says it is made like this:

- Solid 3" visco-elastic memory foam comfort layer molds to your body shape and weight for increased circulation and support

- Reflex™ 7" hypo-allergenic high density foam provides long lasting durability and support

Does this sound like something that will break down horribly? It has good reviews as a plain old mattress on the Sam's site, and we figured that by putting more latex on it we would probably make it last longer anyway. Any ideas on what the "high density foam" might be?

I'd appreciate any input!