Over the last couple of years, we've seen Amazon and Walmart clap back at each other quite a bit, testing out new ways to get their goods to customers more efficiently, more cheaply and more quickly. While Amazon has explored drive-up and automated grocery stores, Walmart has tested out automated grocery kiosks. Both have tried out letting couriers place delivery orders inside customers' houses. And while Walmart has played with having employees deliver your packages on their way home from work as well as sending them through Uber and Lyft, Amazon recently launched free, two-hour Whole Foods delivery in some markets. Both are also now offering meal kits.

While Amazon works on expanding its Whole Foods delivery service, it scaled back its Amazon Fresh service at the end of last year. Meanwhile, Walmart bought an NYC startup last year so that it could start offering same-day deliveries in the city.

Walmart says that it already employs over 18,000 personal shoppers that gather and pack customers' online orders and thousands more will be hired this year as its online grocery shopping offerings expand. The delivery service requires a $30 minimum order and comes with a $10 fee. "Ninety percent of Americans live within 10 miles of a Walmart store, and we serve more than 150 million customers a week, which gives us a unique opportunity to make every day a little easier for busy families," Tom Ward, Walmart's VP of digital operations, said in a statement. "Today, we're expanding this promise by helping even more customers save time and money without leaving their homes."