But somehow this isn't a problem in the EU. I can order from Germany? Spain? Italy? Yet the price is what is shown 'on the sticker'. Of course there are delivery charges, which seem to vary quite a lot (though often free for big ticket items).
In the US the sales tax rate can vary by city, county, and state. Aside from shipping charges, the shipping address is needed to know which governments need to be paid how much.
I suspect it might be how taxes are organised - in the EU we have VAT, so paid to the government where the good/service was created, but in the US it is sales tax, so paid to the government where the good/service was purchased. That's my guess anyway.
Although VAT ultimately flows to where the value was created the consumers are paying tax when they purchase the final product. If I buy a loaf of bread, a sausage, a "home made" cake and a bottle of Coke at the Polish store, the tax for me, the consumer, is local tax.
It isn't necessary for me to know that the sausage actually came from Poland, the bread from a specialist bakery six miles away, the "home made" cake actually was made in the proprietor's home surprisingly albeit at some scale, while the Coke travelled second furthest in its current form, from Wakefield in Yorkshire, over an hour away. These things matter in terms of the onward destiny of the tax money -- Poland gets tax revenue for producing sausages, but not for the bread made to a Polish recipe in a foreign country -- but to me the consumer they're irrelevant.
