This bulk retailer is the pinnacle of savings across the United States. With cavernous aisles and wholesale prices, shoppers flock here for everything from food to furniture. There's a ton in between of course, including clothes, electronics and even books. Already known as a members-only experience, it should be noted that joining Costco entitles you to cash back with every purchase, making it one of the best-valued loyalty programs around. Please note that this loyalty program typically works for all your purchases at Costco, but some exceptions may apply.