Disposable camera
Disposable or single-use camera is a simple box camera meant to be used once. Most use fixed-focus lenses. Some are equipped with an integrated flash unit, and there are even waterproof 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. The cameras are returned for "processing" in the same fashion as film cameras.
In general the one-time-use camera represents a return to the business model pioneered by Kodak for their KODAK camera, predecessor to the Brownie camera; it is particularly popular in situations where a reusable camera would be easily stolen or damaged, when one's regular camera is forgotten, or if one cannot afford a regular camera.
History
A company called Photo-Pac produced a cardboard camera beginning in 1949 which shot 8 exposures and which was mailed-in for processing. Cameras were expensive, and would often have been left safely at home when lovely scenes presented themselves. Frustrated with missing photo opportunities, H. M. Stiles had invented a way to enclose 35mm film in an inexpensive enclosure without the expensive precision film transport mechanism. It cost $1.29. Though incredibly similar to the familiar single-use cameras today, Photo-Pac failed to make a permanent impression on the market.