There are now 10 Amazon Go staff-free, checkout-free stores across the US. The stores are a step beyond self-serve tills, and could spell the end of queuing at the supermarket, and the need for cashiers or supervisors. Amazon Go’s ‘Just Walk Out’ shopping experience is powered by an app which allows customers to enter the store once it is downloaded. The app then tracks the products you pick up around the store and charges your account later, so that you can walk out with your purchases as easily as you walked in.