https://marco.org/2009/02/27/pictured-left-to-right-kindle-2s-power-usb
Pictured left to right: Kindle 2’s power/USB port, its Micro-USB plug, and a standard Mini-USB plug for comparison.
Minor correction: The Kindle 2’s power/USB cord does not end in a standard Mini-USB plug. It’s the new Micro-USB type. (thanks for pointing that out, Ben Gold!)
At least Amazon only charges $15 for a set of one cable with an AC plug — for comparison, Apple sells the cable/plug combo for $30.
There’s one saving grace for multi-gadget owners: iPhones and Kindles both connect to their respective AC power plugs with standard USB plugs, so the AC plug cubes are interchangeable in case you forget, lose, or break one. (In fact, iPhone owners needing only an Apple AC plug, without the cable, can just buy the $15 Kindle cable set and use the plug that comes with it.)