Abstract: A tray which, in one preferred form, may be sized to hold a flat food product such as a pizza. The tray, in this one preferred form, includes a pair of opposed side walls each being foldably connected along a base edge at a generally right angle to a floor. A corner wall is foldably connected to each end of each side wall and also is oriented at a generally right angle to the floor, each corner wall also being oriented at an angle relative to its connected side wall. A set up panel is foldably connected to a bottom edge of each corner panel, is foldably connected to the floor, and overlies the floor in flush relation when the associated corner panel is oriented at a general right angle relative to the floor. A fastener system directly connects each set up panel with the floor. When each set up panel is so fastened to the floor, the side walls and the corner walls are retained in generally upright, i.e.