Vending machines cost a lot of metal, but do not take up much electricity. They dispense treats (like crisps/chips, chocolate bars, fizzy drinks, etc). However, the supplies for them need to be supplied from trading vessels. The supplies come in the form of 'junk food'.
These increase colonist's happiness and may even cancel the negative effect from nutrient dispensers.
These increase colonist's happiness and may even cancel the negative effect from nutrient dispensers.