A drinks dispenser? It's not a term I find myself having to use frequently. Or... ever, that I recall!
Not often for me either, just when it isn't working or has some general problem at a restaurant and I need to tell the staff. (I don't remember the one behind the counter at the pizza place I worked at ever having a problem).
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No customers at the register, so I took a survey of my regular breakfast places' employees about the thing that lets customers fill their cups with any of Coke, Diet Coke, Coke Zero, Lemonade, Powerade, or Sprite*:
2 Soda Fountain (I'm guessing the older two of the five - maybe in their 30s?)
1 Soda Machine
2 Coke Machine (but would have been Soda Machine if it didn't say Coke on the side - including one that would use Soda Machine if it said Pepsi on the side)
They got busy before the follow up and ____ Machine seems to be the term for them for the thing you put money into and then get a can or bottle out of. From the looks on some faces, it also feels like if I were doing a large scale survey I would: (1) Not ask it in front of other future respondents, (2) Randomly ask 1/3rd with the liquid dispensing kind first, (3) Randomly ask 1/3rd with the can/bottle dispensing kind first, (4) Randomly ask 1/3rd using a picture of both at the same time.
* The Sweet Tea and Unsweet Tea are brewed there and go in their own separate dispensers (I'm resisting the urge to ask what they call those). For those outside the US, in the Southeastern US they typically use black tea and served with ice. Sweet tea apparently commonly has 1/2 to 3/4 the sugar of common sodas. Many places that sell bottled teas will have an "extra sweet" option to.
What term do you use for this machine?
Log Cabin? 
