A folder provides easy access to its contents, is lockable, and keeps its locking mechanism out of the way when not in use. The folder has fold lines partway down on the front and back faces, so that the user has easy access to the folder contents. There is a gusset on the bottom edge and on the side edges from the bottom to the fold lines. The folder has an elastic member that is configured to act as a locking mechanism. In the locked position, the elastic member extends over the top edge of the folder, thereby preventing the front and back faces from being folded down and additionally preventing the folder's contents from escaping along the top edge. In the unlocked position, the elastic member extends over the side edges of the folder, and the user may optionally fold down the front and/or back faces and may access the contents through the top edge of the folder. The user can easily move the elastic member from a side edge to the top edge and back, to lock and unlock the folder. In both locked and unlocked positions, the elastic member lies flush along the exterior of the folder and does not dangle freely.