I want to get the new iPhone and the apple watch?

I want to get the new iPhone 6s plus and the apple watch. Will going to New Hampshire save me on the iPhone upgrade plan with the tax that will be due… Will no sales tax up there be applied to that plan, I know the watch will be tax free since I will be paying in full. Just wondering on the iPhone since its financed.

This may help
http://nhpr.org/post/nhs-tax-free-shopping-may-hamper-some-iphone-buyers