(ebay) car parts business please help?

(ebay) car parts business please help?
Hi my son wants to start a company with a friend if you are a mechanic or sell auto parts then you will be a big help. we are just trying to get an idea really of which parts of a car are most bought on ebay or other auction sites the company will sell a range of used and new authentic toyota parts at a discount price
=====================
Car Parts|Auto Parts