Net purchases is equal to the gross purchases of goods from suppliers less the amount of purchase returns, allowances, and discounts. To arrive at the total cost of goods purchased the business needs to add the cost of freight-in needed to deliver the goods to their present location and condition ready for sale to customers.
At the month end a business needs to be able to calculate how much profit it has made. In order to be able to do this, the accounting records are closed and the temporary income and expenses accounts balances are transferred to the income statement.
The cost of goods sold sometimes abbreviated to COGS or referred to as cost of sales, is the costs associated with producing the goods which have been sold during an accounting period. The items must have been sold otherwise there is no cost of goods sold.