Dude... I had a deal like that happen Friday morning.
I've got my 92 Range Rover (not running, needs a fuel pump) for sale at the end of my drive. I woke up to let the dogs out, and I see a guy checking it out. I went and chatted him up, and told him I'd take a $1k for it. He counters asking if I'd be willing to do a trade, and mentions firearms. He has my attention, and names a few things. I tell him I'll take his Mossy Persuader Breacher, and his Saiga 12 (both supposedly new in box). He accepts, and tell me he's got to run back into town to pick up the guns and get in touch w/ a tow company. I get the thing ready to go, and he never calls. By 5PM, I call him to see if he's coming or not. He tells me something came up, he'll need to come look at it again, so on and so forth...
I guess the deal isn't totally broken yet, but I was psyched about my new shottys.