the present invention is directed to a bag having an outer unitary piece of flexible plastic material including generally rectangular front and rear plastic panels and a gusset connecting the panels at a first end portion of the bag , and an inner unitary piece of flexible plastic material including generally rectangular front and rear panels and a gusset connecting the last - mentioned panels at the first end portion of the bag . the ends of the inner and outer unitary pieces of flexible plastic material opposite the first end of the bag are open to facilitate introducing goods into the bag . the side edges of the gussets and the panels are connected together so that the bag when filled can approximate the shape of a hexahedron with the gusset of said outer piece of flexible plastic material being flattened and closing the first end portion of the bag . at least a portion of the outer unitary piece is frangible so as to facilitate access to the goods in the bag and thereafter permit reuse of the bag . a closure device is connected to the outer unitary piece so as to prevent access to the goods in th ebag when the closure device is closed and for facilitating access to the goods in the bag when the closure device is opened .