There is a way to create a US Paypal account. You then can use that US Paypal account to buy from Best Buy.
However since it will require a US prepaid card which is somewhat expensive, this method will only make sense when Best Buy has a sale like 20% off.
Choosing a US address in which state is matter since some states like OR (Oregon) or DE( Delaware) do not charge sale tax while others charge from 5% to 10%. So do not choose the popular ones like CA (California) or NY (New York)
You pay sale tax for every purchase made from iTunes store unless...
A rule of thumb is you should upgrade if you watch/stream video on iPad a lot to be most benefit for the Retina screen. Otherwise hold on your iPad 2 and wait for the next one.