The Camshaft/valve assembly is constructed from several parts from which the Shaft,rr Cam is the most expensive.
Some items from this specific schematic: Plug,rocker Shaft, O-ring, 19.8x1.9, Spg,ex,valve Out., Valve,exhaust.
The lowest price component in this Camshaft/valve parts-list fiche is the Spg,tapet Adj Ass.