A retractable caster assembly includes a frame and a caster wheel assembly. The caster wheel assembly has a wheel and two guide members. The assembly is configured with the guide members movable along slots within the frame so that when the caster wheel assembly is at a first end of the slots the wheel is in a retracted position substantially within the cavity, and so that when the caster wheel assembly is at a second end of the slots the wheel is in an extended position extending from the cavity. A package may have at least one cavity, each cavity for receiving a retractable caster wheel assembly to make a wheeled package.