Had a craigslist add up for a 24" iMac computer. Syracuse, NY area. I get a text from a guy that wants it. I set up a time and place. He shows up, late, I hand over computer and he hands me 4 $100 bills. I immediately look for the water mark... none. I turn around and the guy is speeding away. So off to the local Secret service field office to surrender bills and then to police station to file the crime. Luckily I have the serial number of the computer, but I don't have much information on the guy. I have a cell number, but I doubt its his, could be a burner phone. Needless to say I took all my adds down until I can figure out a way to avoid this from happening again. Which may not be possible. Expensive life lesson...