Quack medical devices using magnets have been around for centuries. I have yet to hear of one that works. Other variations include pads you plug in which create a magnetic field that is supposed to fix you up. None of them have been fda approved, none have been patented for the alleged cure they provide.
People are subjected to very strong magnetic fields when they get a cat scan or mri. Has anyone been cured just by taking one of those procedures? I haven't heard of it. Magnetic fields can affect the body, this has been shown. But, to say it has some effect and to say it cures or benefits in some way are two different things. $350 to sleep on magnets? The money would be better spent on vitamins and good food, imo.
When a controlled study is done showing a benefit, I will look into it and maybe try it myself