I had my Mazda B2300 listed for a bit this year. Its a 1996 truck, 212K miles, I listed it at $3000... phone didnt stop ringing. Didnt end up selling it though - I chose not to.
Fastest car I sold... oh boy, I dont know. My E39 M5 went to the second person who asked about it. My Z3M was bought sight unseen. Ive orchestrated a trade with someone solely via text message with a friend's Honda Accord for some random craigslist person's 95 M3.
I think I am more often the other guy on the transaction... when I go to buy a car I know what I want and bring cash ready to buy. Im the guy who shows up with cash and loads your car onto my trailer within 3 minutes
On more than one occasion I had people come and stop me while I was loading the car on the trailer because it seemed too good to be true to them... thought I was scamming them, lol! Have bought a few cars like this sight unseen from other states as well and driven em home.
Come to think of it, I bought my Z4 the day it was listed and paid only 10% less than asking price. I was the first person to look at the car.