The "Kola Kong" vending machines are pre-Apophis objects featured in RAGE. They are found in several locations throughout the Wasteland, both in the Campaign and the Wasteland Legends. They are very similar to ATMs in the way they are used in-game.
Any active vending machine can be looted for cash, bringing up to $25 to the protagonist. They reset each time the players enter the level, and are therefore an easy source of cash. The amount of money found within appears to vary.
All the vending machines found in the co-op, and some of them found throughout the Campaign, are inactive and cannot be looted. For example, some unlootable vending machines can be found in the Ghost Hideout, near the entrance on the ground floor. However, most of the machines are lootable.