You're a bad negotiator, and you expected 'the good will of nice people' to carry you through this transaction, and you failed.
#1, list everything for 10% more than you want to get out of it.
#2, People are paying cash, and don't want to carry 10s and 5s. List things for $550 if you want $500. List things for $225 if you want $200.
#3, if the kid brought a friend and a truck, you should know that he's not willing to walk away. Stick to your price.
It's a little dance. Learn how to dance!
And, at the end of the day, your mattress is gone, and you have cash. Have you ever tried to throw away a mattress? It sucks, so you did at least that part right!!!
It's great when folks show up and pay asking price, but it's the exception.
