I spoke of the site Gazelle in an earlier post; essentially an automated market place for trading in used electronics. I mentioned I was going to use it to trade in two phones. I had logged in and they had made two offers (one for each phone), which I accepted and that kick started the next phase of the process.
Two boxes arrived at the address I specified, suitable to ship the phones back in. Instructions were clear and unambiguous, and everything required (from the postage label to a sticker to seal the box) was included. I posted the boxes back on Monday, was notified by e-mail Thursday morning, and paid Thursday evening! Now that is prompt. A great service :-)