Meanwhile, the shenanigans in US advertised pricing allows for enormous hidden costs - think cellphone, cable or telephone bills.
How does that work for online advertising and online shopping sites? Most of Europe uses destination based VAT for remote sales, which could make it very difficult or annoying to include VAT in the advertised price if the ads or shopping site reach more than one country.
That's not unusual, American companies do that, too, in order to calculate sales tax.
You probably need it anyway to calculate shipping.
And if you are Amazon, you then give the diff as a discount if it was more than advertised.
VAT just isn’t particularly hard, as business problems go.