Where can someone buy a refurbished iPhone? When I go to Apple's webpage for refurbished and clearance products, I can find links to buy Macs, iPods and iPads, but none for buying refurbished iPhones.

Is it possible to buy a refurbished iPhone:


online, on the Apple Store?
in a physical Apple Store?
online or offline with a phone carrier?
other options?
If you live in the UK (and presumably Europe), SmartFoneStore is a very good place to start looking for refurbished smartphones including iPhones. I believe the refurbs are classified as Grade A, B and C and are priced accordingly.