The production cost for a repair part is almost nothing, because the cost of producing the part, has usually already been budgeted to be covered in the manufacture and sale of the vehicle.
They do include costs for: materials, packaging, warehousing, inventorying, multiple shipping costs, middle man, and retail markups.
I Have considerable experience in the auto repair field. A While ago, when I looked up a lot of the parts prices on my compact tractor, I found they are roughly 2 to 3 times what a comparable automotive part would cost.
The shippers, middle men, and the retailers, need their profit on the parts to be able to exist. But I can't help but feel the manufacturers, at least in better economic times, are profiteering on our misfortunes.