Some items from this specific schematic: Piston-engine L,0.50, Crankshaft-assy, Circlip-piston Pin, Ring-set-piston L,0.5.
The Pin-dowel,4x8 is the lowest priced item on this Crankshaft/piston(s) schematic.
The Crankshaft/piston(s) assembly is constructed from several parts from which the Crankshaft-assy is the most expensive.