WINSTON-SALEM, North Carolina, June 5 -- Wake Forest University issued the following news: FEATURED NEWS How can Costco sell gas so much cheaper than other stations? By Melissa Leonard Hall | Winston-Salem Journal Economics professor Todd McFall explains how Costco can afford to charge less than other gas stations. "All Costco purchases, from gasoline to granola bars to grapes, fall under what's known as a two-part tariff. Part One is the membership. Part Two is where the customer decides to  more