Purse.io
How it works
Firstly, when you wants to use bitcoin to purchase items for a discount from Amazon, you deposits bitcoin in your Purse.io account. Then, using a 'share' URL, you imports your Amazon 'wish list' into Purse.io and indicates what level of discount you would like for the items.
you need to make your amazon wishlist publics for that.
When complete, the listing is posted on the Purse.io marketplace.
Next, someone looking to obtain bitcoin for a similar amount, accepts the transaction and purchases the items on your wish list using a credit card. Soon after, the items are shipped to you.
Once the items have been received, Alice notifies Purse.io, at which point your bitcoin is released from escrow and is sent to the person that purchase from amazon for you.
It is worth noting that while there is a recommended 25% 'maximum' discount, in fact, the user sets the amount and transactions have been accepted with discounts as high as 45%.