Vending Machines are dispensaries that allow a customer to purchase various items within them for indicated prices.
The interaction comes from the customer putting the correct amount of money into said machine and following the onscreen commands to input the corresponding number in relation to the item you want. Generally these are found in forms that dispense food and drinks, and are located in locations that have high through traffic to attribute to the amount of people.
They came into fruition in the early 1880’s of which the first commercial coin-operated vending machines were introduced in London of which initially dispensed post cards. They made there way to the United States in 1888 and primarily sold Tutti-Frutti gum in the subway platforms of New York City. The modern day food and drink dispensers didn’t start to come into light until the 1920’s.
Bellis, M. 2014. The History of Vending Machines. [online] Available at: http://inventors.about.com/od/uvstartinventions/a/vending.htm [Accessed: 13 Jan 2014].