Some items from this specific schematic: Washer-spring,10mm, Nut,6mm, Washer-spring,6mm, O-ring.
The lowest price component in this Turn Signals ('79-'81 C2/c3/c4) parts-list fiche is the Washer-plain,6mm.
The most expensive part in this assembly is the Lamp Assy, Turn, Rear.