I am torn between the Keg King and the link Sam provided. I guess it depends where you are in the US, but I can get a ball lock keg with new popit and gaskets for $28.50 from hombrewing.org. I suspect that if I order 2 or 4 the shipping cost per keg will come down. That seems like a deal. They say they are cleaned, but I am not sure how clean?!?!
The Keg King is $75 for four cornelius kegs including shipping, and while the guy assures me they are pressure tested, they will need new gaskets and probably popits.
Seems to me that if you can get them for $25 with new gaskets and popits delivered to your door, you are doing well.....just my opinion from my research.
Gilbey