Some items from this specific schematic: Screw,tapping,3x12, Grommet Screw Po 4mm, Screw,tapping,(po)4x, Cable Temp Contl.
The lowest price component in this Heater Control parts-list fiche is the Screw,tapping,3x12.
The Heater Control is made up of components including this Contl Assy Htr which is the most expensive.