Some items from this specific schematic: Bulb(12v4w), Screw,spherical, Bulb(12v60/55w,h4), Gasket (nas).
The component with the lowest price in the HEADLAMP (E18,E34) schematic is the Screw.
The Headlamp (e18,e34) is made up of components including this Headlamp Assy which is the most expensive.