Here's are two below the cheapest single bed seen on Casper that runs you $500.
A Foam Queen Mattress for $189 https://goo.gl/YLChia
King or Queen $440 and below https://goo.gl/KNGwQG
A Foam Queen Mattress for $189 https://goo.gl/YLChia
King or Queen $440 and below https://goo.gl/KNGwQG
You proved the statement to be false. Not to mention, what you have posted are coil mattresses. Companies like Casper and Tuft mark-up quite a bit if AliExpress is "warehouse" pricing, but it's really not outrageous.