Since Apple rolled out Apple Pay in October 2014, more than 220,000 retailers have partnered with the company to offer contact-less mobile payments, letting Apple devices wirelessly communicate with checkout machines using near field communication (NFC) technology. And it's not just nationwide chains like Whole Foods Market or Foot Locker. Small businesses can adopt Apple Pay to ensure their customers' security, attract and cater to a younger clientele, and even revolutionize the way customers shop. "It's basic economics," said Bruce Freeman, an entrepreneur who teaches at Seton Hall University (and occasionally contributes to The Week).