eBay: $500 Amazon.com Gift Card that sold for $563

Here's a completed e-bay listing for a $500 Amazon.com Gift Card that sold for $563. Double-WTF? I e-mailed the seller to get his/her perspective. BTW - anyone want a $500 Amazon.com Gift card for, say, $550 ($13 saving!) drop me a line. I have an infinite supply...