If you are in the US, you get charged your state's Tax no matter what, at least that's what I get out of it. With more states passing laws that require web-sites that do business (in whatever form) in the state to collect sales tax. This is to recoup the sales tax that they are not getting from you doing your business online instead of going to a store. (I know my 3DS charges for Wisconsin's state tax when I buy things. (5-to-5.5%, depending on the county)
If you are going for cheep tax rates I think the certal US states and South Eastern states (with the exception of FL) have the lowest taxes.
http://www.retirementliving.com/taxes-by-state (This may help, I wouldn't go with one that doesn't have sales tax since they may charge for CA's sales tax as default.
