Happened to us when we bought ours back in 2009. I looked on CL every day for 4+ months, waiting for the right one to pop up. Once I saw it I called and somehow got the dealer to take a deposit over the phone and hold it for me, by the time I got there later that evening they said they had over half a dozen calls about it and others wanted to show up that evening too, but I put a deposit first.
Same thing again when I bought my 75 hilux - in the 8hrs between scheduling with the seller and me leaving with a new truck, the guy got 5 separate calls, 3 of which were during the test drive. One guy was going to come from out of state!
Sometimes you just gotta make the decision on the fly and buy it before someone else can snatch it from under your feet.