BadgerBrigade - look through the DIY section of these forums for "mini fridge kegerator build" and that should help.
But for those builds you are looking at:
* CO2 Tank
* CO2 Regulator
* Gas lines, barbs, clamps and Quick Disconnects (the things that actually attach to the keg)
* Fridge
* Tower with tap(s)
* Tap handle(s)
* Drip tray
Outside of the cost of the fridge you could probably do it for $250 - $300 or cheaper if you're thrifty
But for those builds you are looking at:
* CO2 Tank
* CO2 Regulator
* Gas lines, barbs, clamps and Quick Disconnects (the things that actually attach to the keg)
* Fridge
* Tower with tap(s)
* Tap handle(s)
* Drip tray
Outside of the cost of the fridge you could probably do it for $250 - $300 or cheaper if you're thrifty