In October, Nicole eliminated all existing inventory of cosmetic items. The trouble of ordering and tracking each product line had exceeded the profits earned. In December, a supplier asked her to sell a prepackaged spa kit. Feeling she could managea single product line, Nicole agreed. Nicole's Getaway Spa (NGS) would make monthly purchases from the supplier at a cost that included production costs and a transportation charge. NGS would keep track of its new inventory using a perpetual inventory system. On December 31, NGS purchased 15 units at a total cost of $7.40 per unit. Nicole purchased 50 more units at $9.00 in February. In March, Nicole purchased 20 units at $11.00 per unit. In May, 60 units were purchased at $10.80 per unit. In June, NGS sold 60 units at a selling price of $13.00 per unit and 60 units at $11.00 per unit