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
If you buy an off brand I would also buy enough replacement consumables to last a a year or two. Which should be the lifetime of the unit. That will give you enough time to save for a good name brand. But then I would have to agree with the rest. Buy once and do it right.
A 89 yj with a 4.0 aw4 sye out of an 92xj. Now the hard part is done time to get it up in the air just a bit. Working on 8.8 with 3.73 and lsd for the rear. and new D30 hp with 3.73 .
For those who have not figured this out I'm old school but can handle the new too.