Costco Wholesale Corp. /zigman2/quotes/201191698/composite COST -1.85% on Wednesday said its net sales for September were $21.46 billion, up 10.1% from $19.5 billion during the month a year earlier. Same-store sales for the membership warehouse chain rose 8.5% for the retail month, which covered the five weeks ending on Oct. 2. U.S. same-store sales rose 11.2% over that time, with a 5.7% gain in Canada. Same-store sales slipped 1.9% in other international locations. E-commerce comparable sales nudged 0.7% higher. The company reported the results as rising prices help lift revenue. Shares were up 0.06% after hours to $480.60.