Amazon has a new private label brand, with many items under $5

Amazon is launching its own private label brand, Amazon Grocery, a move to challenge Costco and Walmart in the growing cost-conscious sales competition.

Shoppers have continued to opt for more private label, or store brands , over name brands, with private label brands accounting for about one out of every four grocery products purchased in the U.S. last year, according to the Private Label Manufacturers Association .