A common vtiger customization we do is to update the Purchase Order to use cost. Vtiger standard shows the unit price from the product record — that is the price you would sell at not the price you will buy at (pay your supplier).
So we add cost as a custom field, change the PO column header to ‘Cost’, and change the vtiger code so it loads/shows the cost when you add a product — not the unit price.
Contact us if we can help you with this.
