A lockable, removable cassette is described. In an implementation, the cassette includes a plastic shell and a currency access door. The cassette may also include a flexible handle and/or an integrated grip. In addition, the cassette may include at least one of an aperture and a transparent window positioned to reveal the contents of the cassette. In an implementation, the cassette includes a stacking mechanism which may include a drive means having non-circular drive gears.