Vending machine providers started building cellular modems into their equipment and buying data in bulk from service providers. A cellular modem is essentially a cell phone, without the phone part. It’s sort of like the cellular connection you may have on your tablet. The amount of data used by each transaction is so small that the vending machine supplier can get it super-cheap. They pass the cost along to you in the form of a few cents more for each bag of chips or each drink.