I have 2 of the $200 FEG marked clones that are great shooters.

http://www.gunbroker.com/Semi-Auto-Pistols/BI.aspx?IncludeSellers=2621012

for example, this one was $350

For me, I'd look through the CDI listings, and I would sort on price.  Then, open each listing up one at a time and look for ones in the pictures that have only minor or no pitting.  He has lots with some pitting that would work ok, but would look too rough for me to be happy with.

I would also look for ones that had a matching sn on the slide and barrel--not essential but my preference. Also, I'd get to know the difference between the early style HiPowers with the ring hammer and the smaller safety and the newer with the spur hammer and longer safety. Pick the one you like better.  Coles (CDISales) usually put on Hogue or Pachmyer wrap around grips if the originals have problems, so look for your preference.  One of mine came with wood which looked good but felt really wide, one came with pachmyers.  I changed out the one with wood for a set of slim Navidrex from Bownells, which felt great.

Some of CDI's are blue, some are parked or reparked.  I have one blue and one parked.  The blue is nicer, but needs a reblueing sometime ( I have oxpho waiting in the garage for some spare time).  The parked one was a refinish, and is now my beater with the pachmyer grips.

Basically, you have choices.  Decide what you want.  Generally, from my research, he grades them worse than they turn out being.  If he gives it a "fair", many people would call it "good".  My barrels were all very good, but the barrel hoods were discolored.  I took a little stainless cleaner and green kitchen scrubbie, and the barrels looked as good as new once I shined up the hood (the part you see through the slides when the slide is closed).

IM  or reply if you have specific questions or want more help sorting.  There are several threads here at arf.com on Coles, as well as some other forum sites.  He seems to have a good rep, only a few issues from around the time he had the break-in and when he was shot.