back around 1970 or so, i was told by the manager of the best parts store in town [there was six or seven at that time] there was 100% mark up at every step of the part [every part] transmission from the manufacture to the selling store. so, for example, if you bought a part for $10.00, the total mark up, at 100% for every stop made at various warehouses and distribution points, means that particular part was only [possibly] pennies to make. i don't know if that is true today, but i think it may be pretty close.