Although the number of items that qualify for next-day delivery is limited, they include products people frequently purchase such as diapers and liquid detergent. They'll find toys and electronics in the separate tab for the feature, as well, though the items available will vary depending on their location. Customers simply have to make sure all the items in their cart are from the curated list to be able to quality for next-day shipping.

Walmart says introducing the feature is a smart business move for the company, because it actually costs less to ship out multiple goods in a single box from a fulfillment center located closest to the customer than to ship out multiple boxes from all over the country. The retail giant will roll out the offering to more locations in the coming months, including 40 of the top 50 major cities in the US, with the intention of making it accessible to 75 percent of the US population by the end of the year.