It's not just Amazon and Overstock. It's any online business. I just bought a computer online and had to pay sales tax, even though I bought it from a company based in California, with accessories being shipped from somewhere in the midwest. Since I do live in NY, I didn't bitch too much, though I thought angrily that if I could so easily do what you've hinted at, and simply have the thing shipped to my friend in NJ.