The most reasonably priced component used on the Vz800 Boulevard M50 2005 (k5) Usa (e03) Boulevardm50 Boulevard-m Fuel Tank (model K9) is the Cushion.
The most expensive part in this assembly is the Tank Assy,fuel.
Some items from this specific schematic: Shield,fuel Tank Heat No.2, Spacer (8.2x12.5x23.5), Screw, Cushion.