The component with the lowest price in the LOWER CRANKCASE schematic is the Washer,plug Drain 14.
Some items from this specific schematic: O-ring,15x2.5, Bolt,flange,6x50, Bolt,plug Drain 14mm, Crankcase (lower).
The Lower Crankcase is made up of components including this Crankcase (lower) which is the most expensive.