Collapsible storage device and system having a container with a planar section and side wall pivotably joined to the base so that the container is movable between a collapsed configuration in which the container is substantially flat and an expanded configuration defining a top opening and a side opening to an interior of the container. The storage device further includes a cover frame. Locking members are provided for securing the frame to the sidewall to close the top opening of the container and to form a rigid structure. The locking members include a complimentary shaped locking tooth and slot. The storage device is further provided with a closable flap or door which provides access to the interior of the container through the side opening when the container is in the expanded configuration.