According to people familiar with the matter, the company could have 10 locations running by the end of the year and as many as 50 in 2019. One major hurdle, however, would be the cost -- Bloomberg's sources said the first Amazon Go store needed more than $1 million worth of hardware. Focusing on prepared foods rather than groceries could help boost profit margins, and some of the existing stores are already doing that. Additionally, opening multiple stores in the same metro area could help minimize costs since they could in theory share a centralized food production facility.

Bloomberg notes that with Amazon's focus on dense metro areas, those likely to be affected by the cashierless stores include businesses like Subway, Panera and Pret A Manger -- restaurants that allow for quick eating or convenient takeaway.

Amazon currently has little competition when it comes to its Go stores, though that could change soon. Microsoft reportedly has its own checkout-free technology in the works and Standard Cognition opened up a cashierless store in San Francisco earlier this month.