You can buy most merchandise from outside US without paying sales tax. Sales tax for e-commerce has been a debate for a long time.
Even though the legislation is talking about such, the force from both support and opposition is strong enough to make it long process. The current bottom line is, only if both buyer and seller are from the same state, then seller will have obligation to collect sales tax.
However, this is never the case for shoppers outside the country.
Therefore, argue with your seller for free tax if some sellers attempt to charge you tax.
In addition, most sellers offer free domestic shipping. If your seller is not doing that, ask for it.
With a free mailing address provided by America-ship.com in Brownsville, Texas, you enjoy both tax free and shipping free.