Some items from this specific schematic: Cable W/v Contl, Core Comp Heater, Screw,tap., Motor Assy A/m.
The sub assemblies and components that make up this Heater Unit include this Heater Unit Assy, the most expensive part.
The most reasonably priced component used on the Civic 2000 (y) 4dr Ex (ka) Heater Unit is the Screw Tapping 5x12.