On May 1, Cullumber company had the beginning inventory consisting of 252 units with a unit cost of $5. During May, the company purchased inventory as follows: 504 units at $5 ,756 units at $6. The company sold $1260 units during the month for $9 per unit. Cullumber uses the average cost method. Assuming that a periodic inventory system is used, the cost of Cullumber's inventory at May 31 is