Changes

The used (craigslist) market is available without a prescription, but the choices and prices are all over the place.

In the US a prescription for CPAP has been a requirement since the beginning of CPAP use. (CPAP machines are an FDA regulated class II medical device in the U.S., which requires a prescription). In recent years, FDA regulations have also included CPAP masks as an "integral" part of a CPAP and therefore also classified as part of a class II medical device as well (prescription required for those as well). That said it is possible to purchase without a prescription.