These are the international version, so that they will come with the correct adapter plug. Also, note that some Alexa Skills may not be available for all countries.
The Amazon Echo (4th Generation) International Version retails for S$141 with an additional S$18.78 for shipping to Singapore.
The Amazon Echo Dot (4th Generation) International Version retails for S$69.96 with an additional S$12.08 for shipping to Singapore.
Before that, I have to sideload the Amazon Alexa APK to my Android phone to set it up. I know there is a Web UI, alexa.amazon.com, but it is buggy.
I don’t toggle between different regions App Store on my iPhone because I want to keep it simple, and besides, it will mess up my Apple Music settings.