Free-cycle groups - donating items for free?

I use my local free cycle group to donate unwanted items. At the moment I am offering a perfectly good working 15" flat screen monitor and working printer. I had over 26 requests for these items. I am now on my 8th contact offering them the items because of time wasters. Why do people do this? It is so frustrating. You try to help others by donating good usable items only for them never to reply when offered. I don't want to offer it to a charity shop because I know a lot of the workers in there buy good things for 50p and sell them on ebay. Any suggestions please.