Wow, you are all making me very glad to live in the UK. While our refuse services are contracted out to private companies, the govt insists that re-usable or more valuable items are resold back to the public instead of being mashed up in skips with all the other junk.
Every bike I've bought in the last 2 years (bar one) has been from one of my local tips, and they've all either been fully functional bar one minor issue like a siezed cable or shifter or rusty chain or just general cosmetic unpleasantness. Also, they have a big shed full of furniture, toys, some antiques, records, books and everything else there, usually dirt cheap.
The caveat is that once an item ends up in the skip, it can't be retrieved (liability/ insurance) and they won't sell electrical items. But they're entirely responsible for my irresponsible bike buying. Americans, you have my sympathies on this occasion.