You will need to install a user script manager extension to install this script.
It shows real time prices across amazon portals. Prices will be displayed next to the item's price in an appropriate color depending on the value.
The double square brackets indicate the country of the current page/item.
Amazon supported states: [IT,DE,FR,ES,UK,US,CA,AU]
You need to have the google emoji fonts installed in your system in order to see the flags: https://fonts.google.com/noto/specimen/Noto+Color+Emoji