The most reasonably priced component used on the 115eth 1987 Optional Parts Gauges & Component Parts 2 is the Washer, Spring.
With a quantity of two pieces, the Nut, Hexagon (663) is the most used part in the OPTIONAL PARTS GAUGES & COMPONENT PARTS 2 diagram.
Of all the components used in this assembly the Voltmeter Assy is the most expensive.