Costco Wholesale (NASDAQ: COST) has been one of the more resilient retail stocks to invest in during the pandemic, even as inflation has been problematic for businesses. But here's why that might not be true, and how Costco's latest monthly sales numbers may be a little misleading. Gasoline and foreign exchange are weighing down its comparable sales There are many reasons shoppers go to Costco, and purchasing cheap gas is one of them.