The component with the lowest price in the F-21 schematic is the Clip B8,tube.
Parts such as the F-21: Rubber,rad.mount, Tube,vinl,6x9x600, Hose B,water, Radiator Assy are included in the Cr85rb 2003 (3) Japan He07-100 F-21 parts fiche.
The F-21 assembly is constructed from several parts from which the Radiator Assy is the most expensive.