Product costing for bought out or trading goods

Hi SAP Gurus,

Please explain me the process in product costing specially in the case of where only trading goods are available. No manufacturing activities are being carried. I mean to say that only brought out product are available to be costed.

My client is only buying product from the market and selling them to their customer and taking margin as their profit.

Will award good points.

Thanks & Regards,

Manish