Box, I don't know if you have FreeCycle in your area, but maybe give it a look. I signed up last fall and one of the things I got was a queen-size memory foam mattress FOR FREE. I also asked for junk garden hose to use to slow water erosion in my gravel driveway, and in addition to some junk hose, I got a whole bunch of really, really nice garden hose! Can't believe what some folks are giving away, but I guess it's stuff they don't have a use for.
It's an online forum and the deal is that you can post to offer anything but CANNOT ask for money, barter, etc. Has to be FREE, hence the snappy name. You can also post and ask for things you need. In my neck of the woods, I have seen everything from utter junk (or so it seems to me) to things that the owner could certainly have sold for a fair chunk of change but chose instead to offer free. I've both given and received, and in my experience, it's a great way to both get stuff you need for free and keep useful things out of the landfill...