In the US, sales tax varies by jurisdiction, even within a state. If I buy something in my city, it could be 0.10-0.25% difference than the city next door, because our cities will have different tax needs. In my state, sales tax ranges from 7.5-8.5%, depending on where the purchase is made, and the city portion is generally around 1% (state portion is fixed).

It's incredibly dumb, and I wish physical stores were required to display price after factoring in taxes. However, for websites, I don't expect that, simply due to the variability between jurisdictions (makes advertising prices ridiculous), and because it's trivial to see the final figure in the cart after I input shipping information.

So if Brazil includes taxes in online quotes like the EU, the gaps is even narrower. My local tax rate is around 8%, so for me, that $600-700 item would be $650-750, which is still cheaper than Brazil, but Brazil may very well have higher sales tax than here. Ideally, we'd compare w/ pre-tax values for a more apples-to-apples figure.