I have a used ESAB PCM875 that I bought off of CL. Great machine. I'd second the CL recommendation, you really do get what you pay for with plasma cutters. Mine is older, and at some point I may need to upgrade to an SL60 thermadyne one torch, but probably not any time soon. I was able to get it for $500 which is a damn sight cheaper than any well made newer system I could find.
"No man's knowledge here can go beyond his experience." - John Locke
"Vi Et Armis" - Cicero