The disposable or single-use camera is a simple box camera sold with a roll of film installed, meant to be used once. Most use focus free lenses. Some are equipped with an integrated flash unit, and there are even water proof versions for underwater photography. Internally, the cameras use a 135 film or an APS cartridge. While some disposables contain an actual cartridge as used for loading normal, reusable cameras, others just have the film wound internally on an open spool. The whole camera is handed in for processing. Some of the cameras are recycled, i.e. refilled with film and resold.
I receive from store a "disposable camera" for free after I bought 3 bottles of beer.