Natural mattress for a kid: OG from Pure-Rest or Organic Baby vs. cheaper compromise

[sibilant]

I'd like to buy a twin mattress for my son; he's on the top bunk so that the mattress has to be on the slim side. I've been looking at the options on Pure-Rest (for example, http://www.purerest.com/Mattresses/Gemini-Mattresses) as well as Organic Baby, which I think maybe has the same mattress quite a bit cheaper (http://organicgrace.com/taxonomy/term/110) -- about $950 vs. $750, though it's a little hard to decipher if the mattresses are really the same.

Anyhow, I've been trying to decide whether we can afford such a thing, etc., as insanely expensive, of course, when I came across this non-OG alternative: http://www.sleepworks.com/mattresses/childrens. The wool involved is not organic, and the coil pockets are made out of some kind of synthetic material (FAQ from the manufacturer: http://berkeleyergo.com/faq.html) -- but it's under $450, which suddenly doesn't seem so bad at all...

What do y'all think? Does anyone know this particular mattress? Is this a reasonable compromise? Organic things are so nice usually, and I definitely want to minimize exposure to chemicals, but I also don't want to be hysterical about it....  Thanks in advance!

[talia rose]

Yes the mattress we sell at Organic Grace as the Budget 4" Latex is the same as the Gemini sold by Purerest. We sell it under a different name so we can offer better pricing for mamas like yourself. It is our most popular model for kids and we have sold many to Mothering Mamas....