Some items from this specific schematic: Screw-pan Head,6x12, Gasket,exhaust Pipe H (nas), Cap,air Filter, Clamp.
The lowest price component in this Air Cleaner/muffler parts-list fiche is the Screw-pan-cros,5x8.
The Air Cleaner/muffler assembly is constructed from several parts from which the Muffler is the most expensive.