A display apparatus comprises an elongate support member configured to support a plurality of packaged products thereon. A product pusher device is movably supported on the support member for forward and rearward movement along it. The product pusher device has a biasing mechanism therein that engages the support member and applies a relative force thereto from the pusher device such that the product pusher device engages a rearmost one of the plurality of packaged products and applies a pushing force thereto so as to move the packaged products forward towards the distal end of the support member. The biasing mechanism is completely supported in the product pusher device and moves therewith on the support member. The biasing mechanism may be a wheel rotatably supported in the product pusher device so as to engage with the support member and to rotate when the product pusher device moves along the support member, and a spring having one end thereof fixedly connected with a housing of the pusher device, and a second end thereof fixedly connected with the wheel so that the spring is charged when the pusher device is moved rearward and the spring urges the wheel to rotate to move the pusher device forward on the support member. A method for providing a display, including for a retrofit of existing displays, is also described.