Where did you buy your keg and tanks from? I've seen the usual suspects (homebrew sites) that sell a basic setup for ~$265 or so for a 5 gallon new keg, 5 lb. CO2, regulator, and picnic faucet. I've also seen other sites that are not specifically for homebrewing that offer the same equipment.
FWIW, I plan on using the existing chest freezer (fermentation chamber) for the keg. I unfortunately don't have a dedicated kegerator at this point.