Help With New York Tax

Hi
I Have A Usa Address In Myusabox.com And I Am Planing To Use
It To Forward My Items To My Country.they Provided Me With
A New York Address And I Knew Recently That Many Stores Charging
Tax For Shipping To New York Addresses. Is That Right.
I Am Planing To Buy Many Goods And Forward It To My Customers
That Company Really Has Low Shipping Rate But The Tax Well
Really Finish My Business.
Do Anybody Know How To Avoid Tax?
Any Other Mail Forwarding Companies With Same Or Less Shipping
Rate?
Thanks