I'm thinking of buying a used iMac on craigslist since I don't really have enough for a new one or even a refurbished one from Apple. The one I found on craigslist is a Late 2012 iMac for $500 with these specs: INTEL CORE I5 2.7 GHZ 8 GB 1600 MHZ DDR3 MEMORY NVIDIA GEFORCE GT 640M 512 MB 1TB HARD DRIVE What exactly should I look for when inspecting the iMac before buying? Also I've read on a couple of these threads of people advising to take the product to the Apple's genius bar to inspect it and do a diagnostic test. Is that something they willingly do? How do I go about getting the genius bar to check it out? Is it okay to tell them that I'm buying it from craigslist? Any help will be appreciated. Thanks!