A mobile device can establish a communication with a separate device via a single function action such as bringing the devices near to each other. A method can include establishing a communication between a mobile device and a separate device a via a wireless link, presenting an instruction associated with the potential purchase and receiving, after the instruction is displayed and interpreted by the mobile device, a single-function gesture which can be a security measure to prevent unauthorized purchase. The method includes retrieving the payment data from a memory of the mobile device and transmitting the payment data via the wireless link to the separate device to make a purchase.