Surist, Inc. purchased $ 300,000 merchandise, received a $ 20,000 merchandise return credit, availed discounts for $ 5,000, and paid $ 12,000 in transportation costs for the merchandise. At the beginning of the period it had an initial inventory of $ 30,000, and a total of goods sold costs equal to $ 180,000. Determine the cost of the purchased merchandise and the ending inventory balance. Show your calculations.