The Screw,cross,4x14 is the lowest priced item on this Air Valve - Reed Valve schematic.
A sample from the products for the Air Valve - Reed Valve include: Hose (10x280), Valve Assy.,reed, Joint, L. Air Valve, Bolt,flange,6x14.
Of all the components used in this assembly the Valve,air is the most expensive.