The component with the lowest price in the IGNITION COIL schematic is the Nut,hex Cap 6mm.
This schematic depicts all components used in the Civic 2003 (3) 2dr Dx (ka) Ignition Coil partslist.
A sample from the products for the Ignition Coil include: Spark Plug(pzfr6f-11, Nut,hex Cap 6mm, Coil Comp, Plug Hole, Plug Hole Seal.