Recycling unwanted household effects is a big business and will likely become even bigger in the future. In most cases you have to pay to have your stuff hauled away, even by those little trucks that drive slowly around residential neighborhoods calling for people to give them their used computers, stereos, what-have-you. These businesses say they'll take your things for free, but once you bring the item all the way to their truck they usually have some kind of handling fee they forgot about.
There are places that will take your still usable refuse for free; though, of course, they'll be more selective about it. One is Awn (pronounced "ah-oon"; it stands for Asian Workers Network), which is located in Higashi Nippori in eastern Tokyo. Awn started eight years ago as a "recycle shop" whose purpose had less to do with recycling or making money than with jobs.