Yooper said:You just need the kegs, the kegerator, and the co2 system.
A soda keg ("corney keg"), a regulator, the co2 tank, 30' of "beer line", 5 feet of "gas line", a black quick disconnect for beer, a gray disconnect for gas, a faucet (often "picnic" or "cobra" tap) and the fridge should cover what you need.