I'm not quite sure how this has happened, but when I went to buy the Woody Disney Infinity figure on Amazon, the price came up as £0.00 on the Checkout page as a promotion has been applied.
The price is normal when it is in your basket, but at Checkout the figure becomes free.
I have Amazon Prime but haven't got any Amazon credits or discounts so I'm not sure what's happening.
Doesn't appear to work for any other Disney Infinity figures that I have been testing.
Hope this helps someone.