The component with the lowest price in the REAR HUB schematic is the Nut,flanged,10mm.
The Rear Hub assembly is constructed from several parts from which the Axle,rr is the most expensive.
A sample from the products for the Rear Hub include: Ring-snap,95mm, Collar,40.2x45.4x159, Nut,flanged,10mm, Bearing-ball,#6008uu.