Costco Next, an online marketplace Costco members often regarded as one of the retailer’s most coveted hidden perks, has quietly disappeared from the company’s website. The service gave members up to 40% off on certain products not offered at its warehouses. The program featured items from a specific list of vendor partners, ranging from home goods and luggage to electronics.Shoppers visiting the Costco Next online page are now met with a message: "Access to Costco Next storefronts is no longer available." Costco said shoppers seeking to return items previously purchased through the program sh...