If you've ever sold something online, you know that the customers aren't ideal. They text you, 'Is this available?', only to ghost you when you answer in the affirmative. Or they promise to pick it up, set up a date and a time, and then never show up. Or they actually show up with half the money and give you a sob story on why you should give them the item for free. Yes, I'm speaking from experience. One man decided to sell an old laptop he had back from his University days, posting it online,…