Yes, you can buy stuff on Amazon using BTC. There is a wallet called Ipayyou (it is 2 years old age now) that allows you to buy on Amazon using your bitcoins. The wallet has a featured called “Amazon Direct” that lets you transfer any dollar amount of bitcoin to use for purchases on Amazon. I might be mistaken but I think this is the only way, for now, to buy things on amazon using bitcoins.

For more information check:https://bitcoinexchangeguide.com/ipayyou/

or visit : https://wallet.ipayyou.io/