As with any phone buying, check it all out, trust your gut, check the ESN and otherwise cover your ****.
Maybe poke around, check nothings broken that you care about.
May want to check its got the OEM curved display among other parts.
And make sure its a 920, there was a thread earlier about some yahoo passing off a 520 as a 920. Whether maliciously or by ignorance, I don't know.
Wait a minute, I assumed you meant a face-to-face meeting list Craigslist.
