Trey Monson starts a merchandising business on December 1 and enters into the following three inventory purchases. Also, on December 15, Monson sells 23 units for $30 each.

Purchases on December 7	13 units @ $12.00 cost
Purchases on December 14	30 units @ $18.00 cost
Purchases on December 21	23 units @ $22.00 cost

Monson uses a perpetual inventory system. Determine the costs assigned to the December 31 ending inventory based on the FIFO method.