This Tank, Oil (164-21751-01-81) Primer is the most expensive of the items that make up this Oil Tank assembly.
Some items from this specific schematic: Nut 137217620000, Knob, Side Cover (r.h), Gasket 227217670000 (mca), Washer Plate 122217250000.
The lowest price component in this Oil Tank parts-list fiche is the Nut, Latch Clamp.