THE BEST
I like Foam Factory (aka Foam by Mail) for several reasons:
1st. Their prices for top quality memory foam beat the pants off of any other source of memory foam, by a long shot. I have searched and searched many, many times and found no other source gets even close to their prices.
2. I get to choose the density of the memory foam.
One can find memory foam through searches of many platforms like Amazon and eBay, and there are firms which directly sell memory foam mattresses and toppers to consumers like Serta Simmons Bedding, Sleep Number, and Casper, Tempur-Pedic, Amerisleep, Purple Mattress. I am sure many of those offer quality products. But - good luck finding detailed information about the density of the foam. So reason number..
3. Foam Factory posts detailed information about EVERY mattressy foam product they sell, both in the details section on each page, as well as via a direct link to a Physical Data Sheet for each and every foam.
Details include Density (LB/Cubic Ft.), ILD (LB), Tensile (PSI) Min., Fire Retardant properties, Anti-Bacterial and Anti-Fungal properties, CertiPUR-US® Certification, and whether the particular foam Contains Fire Retardant Additives. Good luck finding this on any other manufacturer's or seller's website, really.
When looking to replace a twin size, brick hard compacted futon and 2" of cheap (I can't even figure out where I got it) memory foam, I was actually able to "build my own mattress", selecting the top layer from their "Mattress Toppers" page from among various memory foam densities (3lb, 4lb, and 5lb)
I picked the 2" of 5lb density, (& 12 ILD) , and the mid and bottom layers from among 6 "Conventional foam mattresses"; (HD36-R Foam, HD36-HQ Foam, Poly Foam, Super Soft Foam, LUX-R Foam, and LUX-HQ Foam).
For my mid-layer, I chose 5" of their HD36-HQ Foam (2.8 lb Density, 35 ILD),
and for the bottom layer, 2" of their LUX-HQ Foam (1.8lb Density, 50 ILD).
I also purchased a twin size Gray and White Striped Cover for the stack from Foam Factory.
They were cool enough to put all the layers in the correct order into the cover for me, and shipped the whole "mattress" to me. The resulting mattress is about 9" thick. I weigh about 140lbs, and sink just enough into the memory foam layer to feel the support accommodating my side sleeping body.
In the end it cost only $273.69. They offer free Shipping On All Orders Over $100, so zero cost to me for shipping. It arrived to my home very quickly. I now sleep dreamy, as opposed to sore and almost bruised from my old brick hard futon and 2" memory foam topper.
BTW, I later saw a twin size mattress @ my wholesale club with 3 layers - memory foam, and 2 foam layers for less than I paid. I could find zero info on the package detailing density, or ILD of any layer, so, a crap shoot.
I have been buying from these folks since 2022, (I got a full size 2", 5lb density topper for the bed in my overlanding trailer). I have never been disappointed with any purchase from Foam Factory.