Perk-a-cola machines are make-believe vending machines in the Nazi Zombie level "Zombie Verrückt"
Juggernog
Juggernog is one of the first Perk-a-cola machines on the left sides of the level, it increases your health, meaning that it takes more than 2 zombie slashes to down you. This actually increases it to about 6 slashes, which is very important in most scenarios. Such as past the double-digit levels. According to the machine, the nog is made with real eggs and the catch-phrase is "Take a tug on that sweet, sweet Jugg." This is also the only Perk-a-cola machine not shown in the trailer.
Quick Revive Soda
Quick revive soda is one of the first perk-a-cola machines on the right side of the level. As said by the machine, it's ice cold. Also, it's the only perk-a-cola machine not based off the tier 2 perks from multiplayer. It allows you to revive people faster, which is essential in later levels when people are going to be downed INCREDIBLY often and reviving team-mates in crucial in zombie infested environments marked as "No-man's lands"
Double Tap Root Beer
Unlike most, this is the most common Perk-a-cola to get, but also one of the most useless. It increases rate of fire like "Double Tap" however must weapons are at the peak of their ROF (Rate of fire) however it is bought most often since the left side of the map is usually quicker. The right side usually waits until the left side is done. Double tap root beer is the easiest to get to in that case. On top of being the most useless, it's also the priciest. Costing a walloping 3000 points.
Speed Cola
Speed Cola is based off the perk "Sleight of Hand" and is incredibly useful in later levels where reloading an LMG takes a long time. This combined with every other perk will ultimately lead to success.