I wonder if the free things attract time wasters more than the sold ones.
I tend to use a local recycling site to give away larger items such as furniture, and have often been messed about. People don't turn up, after I've cleaned up the item, moved it to the hallway or somewhere easy to load into a car, and arranged a delivery time. It's so rude. If they can't get a lift or arrange for someone to collect it, the least they can do is let me know. The site is quite strict, too. If you notify the moderators they issue a 28 day ban to time-wasters.
I am not looking for effusive thanks, but I do get a bit pursed of lip when I see some of the replies. People don't even use sentences, or say please and thank you. I once offered a microwave (free) on a holiday park, and the answer was just 'Number?', not 'Yes please', or 'I would like this, where are you situated?'
I don't get upset though - I just roll my eyes and mutter about people being raised by wolves.