Bon Soo Company made the following merchandise purchases during the current year:

There was no beginning inventory, but ending inventory consisted of $400$ units. Show your calculations.

If Bon Soo uses the weighted$-$average cost method, the cost of the ending inventory $=\_\_\_\_\_\_\_\_\_\_\_\_.$

If Bon Soo uses the first$-$in$,$ first$-$out $($FIFO$)$ method, the cost of the ending inventory$=\_\_\_\_\_\_\_\_\_\_\_\_.$