Methods and devices for mobile payment transactions with a product dispenser

A method of using a product dispenser, comprising:

• receiving at a product dispenser via a wireless communication link a request from a mobile device to establish a secure connection between the product dispenser and the mobile device;
• after the request to establish the secure connection is received, receiving from the mobile device, via the wireless communication link, a secure key for secure communication between the product dispenser and the mobile device;
• establishing the secure connection between the product dispenser and the mobile device, wherein the secure connection allows communication between the product dispenser and the mobile device using the secure key;
• and
• in response to receiving an authorized amount of payment for a product from the mobile device, causing the product to be dispensed from the product dispenser, wherein the authorized amount of payment is encrypted using the secure key.