Best Sourcing Methods

Dear All,
I would like to know best sourcing method for an automobile industry. Have just completed my second sem and started with my summer internship in an automobile industry. My project is on "Cost effective sourcing methodology". I would request you all to suggest me the best sourcing method.
Regards,

Dear friend,
Sourcing happens in the automobile company by two departments. While HR department sources the job candidates, procurement department sources the material. Therefore, please confirm for what department, you are looking for "Cost effective sourcing methodology".
Thanks,
Dinesh Divekar