An obvious question: why aren't more CPAP machines generally available for sale to end users? Amazon and Ebay mostly sell accessories. Maybe there's a business opportunity here.
I believe that's partly a government issue. They're considered a prescription medical device. So they can only be sold by specialty stores that can validate the prescription.
I wonder why? Are they significantly risky if used without medical supervision?
The definition of medical device is terribly non-granular, classifications notwithstanding. Something like an IV pump which directly literally kill you if it breaks or is misused is subject to the same kind of sale prohibitions as a CPAP whose absolutely worst failure case is giving you a shitty night’s sleep.