A lot of towns and cities have free/gifting pages on FB and there are so many people out there who would be so grateful for a good clean bed.
My local gifting page is always posting, it's well established and I have got rid of a lot of things on there, furniture, lamps, kitchen items, beds and bedding, I have also picked up some lovely items for our own home, last one being a lovely rattan shelf unit, it's quite well loved but that adds to it's charm.
All the person who's being gifted said item has to do is collect it or arrange delivery, if they ask for it to be delivered by you then you charge fuel money... usually about a fiver, if you can't deliver because your car is too small, then the onus is on them to collect. Most gifting/freebie pages will have similar rules