Full disclosure first: I am with Sleeping Organic, so weigh what follows accordingly.
On your actual question, I do not think anyone can tell you whether $3,500 is a good price, including me, and that is the useful part of the answer. Price only means something next to specification, and the specification is the bit you have not got yet. Four things to ask the store, and the answers will tell you more than any of us can:
- Is the latex natural Dunlop, or blended? Blended latex is mostly synthetic and costs a fraction of natural to make. This single answer moves the fair price for that bed by a large margin.
- What is the ILD, as a number, on each face? It is flippable, so there should be two answers.
- What is the cover made of, and what is the fire barrier? Wool, or a chemical flame retardant.
- Is the latex certified, GOLS or otherwise, and who holds the certificate? The maker of the latex and the seller of the mattress are often not the same company.
If they cannot answer 1 and 2 without checking, that is worth knowing on its own. For a reference point to measure their answers against, our own Dunlop runs X-Soft 14-19 ILD, Soft 19-22, Medium 30-32, Firm 37-40, X-Firm 44. Not a standard, just a published scale you can hold their numbers up against.
Now the thing I would actually flag, which matters more than the money.
You have said you will need a topper regardless, before you have slept on it. That is your own instinct telling you the bed as sold is not quite right for you, and you are proposing to spend $3,500 and then modify it. On a one-piece core, the topper is the ONLY adjustment you will ever have. If the feel is wrong, you cannot change anything inside the mattress, because there is nothing inside it to change. And a 12 inch bed plus a topper lands you around 14 or 15 inches, which starts to fight with ordinary fitted sheets.
To be fair to it, flippable is a genuine durability advantage and I would not talk you out of that. A solid core with two usable faces will outlast a lot of things. What it buys you in longevity it takes away in adjustability, and for a side sleeper the part that matters most is the first two or three inches under your shoulder, which on that bed is fixed at the factory.
So the question I would put to yourself is not “is $3,500 a fair price for this mattress”. It is “what happens if it is too firm in month two”. Ask the store that too. What an adjustment costs after you have slept on it varies enormously between sellers, and it is the question almost nobody asks before buying.
Sleep on Latex, SleepEZ and the layered builders generally, ourselves included, answer that differently because the layers come apart. That is the real trade against a one-piece bed, rather than the price.
Brandon, Sleeping Organic