Originally Posted by
t325
FWIW, sales tax isn't included in prices in the US because each state, county and city has a different tax rate, so there are thousands of tax rates across the country. Companies couldn't then accurately advertise something as a certain price because the price is going to depend on where you buy it. Two neighboring stores could have different tax rates if there's a municipality border between them.
So they can advertise "as low as xx.xx*"
*- if bought in [store in located in a county with the lowest rate]. Or if the rates aren't that different, make the prices the same everywhere and make different amounts on the products. And including sales tax in sticker prices at a store is not that hard.
Online retailers seem to be able to calculate prices if you put in your zip code.