So I am in the market to purchase a Canon 6D with kit 24-105mmL lens, and found a guy on Craigslist who has a bundle he selling. Included is the 6D, 24-105mmL lens, four batters (one OEM, three third party), two chargers (one OEM, one third party), battery grip, and camera bag for $1,500. He claims that the camera and lens are in excellent to near perfect condition, as he does shoots roughly two times a month and always in studio (so not much exposure to the elements). I asked him what the shutter count was, but he didn't know and said that he was estimating around 20,000. He said he is selling as he is upgrading to a Nikon 810. I am obviously very interested in this, and was hoping I could get some advice from some veteran photographers. What should I specifically check/look out for on the camera/lens when I meet the guy tomorrow? Is there a program I can download (for Mac) that I can check the shutter count on the spot? Anything else I should think about that I haven't yet? I really appreciate all he help!