Samuelson and Messenger $($SAM$)$ began $2021$ with $250$ units of its one product. These units were purchased near the end of $2020$ for $$24$ each. During the month of January, $125$ units were purchased on January $8$ for $$27$ each and another $250$ units were purchased on January $19$ for $$29$ each. Sales of $170$ units and $130$ units were made on January $10$ and January $25,$ respectively. There were $325$ units on hand at the end of the month. SAM uses a periodic inventory system. Calculate ending inventory and cost of goods sold for January using average cost.