The component with the lowest price in the FUEL TANK schematic is the Circlip (604).
Some items from this specific schematic: Damper, Tank Locating 1, Washer Plate 178147660000 (mca), Spring, Plate, Fuel Cock Assy.
This part-list fiche shows all the components that make up the Sr500 1991 3eb2 Germany 213eb-332g1 Fuel Tank .