Vending machine for product competition

A vending machine comprising:

• a money deposit opening configured to receive a particular currency deposited therein;
• a money return opening;
• an input part configured to receive a user input from a user for product selection;
• a product dispenser opening configured to dispense a product selected by the user;
• a product competition module configured to determine product competition ranks of a plurality of different products sold by the vending machine by counting a total number of sales or a total sales value for each of the plurality of different products for a predetermined duration of product competition time, and to provide a benefit to a winning buyer selecting a winning product that wins a product competition according to the product competition ranks of the products;
• a controller configured to assign different display periods of time for advertisements of the products being sold by the vending machine in correspondence to the product competition ranks;
• and
• a display part provided on a front side of the vending machine to display the advertisements of the products during the different display periods of time, respectively, wherein a first display period of time for a first product having a higher competition rank is longer than a second display period of time for a second product having a lower competition rank.