5 Mind-Blowing Secrets About Costco Costco is everyone’s favorite warehouse store, and for good reason. They sell everything from bulk groceries to flatscreen TVs to designer clothing. It’s truly a one-stop shop and offers some of the best deals of any grocery store. Costco even loses money on a few of their items to keep customers coming back year after year. If you want to save even more money and have a better shopping experience, here are 5 mind-blowing secrets about Costco that you need to know. 5 Mind-Blowing Secrets About Costco The Best Deals Are in the Center of the Store