Before you sell your iPhone on ebaY, please be aware that the odds are overwhelming that you will have your money held by PayPal for at least 21 days, if not longer.
People looking for other venues to make a quick sale or have their old electronics recycled can search the web. I've recently been seeing TV commercials for various services such as gazelle.com and bestbuy recycling or trade ups.
I understand even Amazon has a new trade in service