The easiest place to still get US Amazon gift cards is https://btcfor.gifts/

One of our affiliates created some Medium posts awhile back:
https://medium.com/@kareninsf2/amazon-gift-cards-are-now-available-for-bitcoin-and-litecoin-ec12a27ef66a
https://medium.com/@kareninsf2/netflix-amazon-and-other-usd-gift-cards-are-now-available-for-litecoin-altcoins-and-bitcoin-da34bb509523


Hope this helps!