Paying tax in best buy?

So I'm going tomorrow to Best Buy to buy a Nikon D3100. The price right now is $645.99 & all I have is $700. I wanted to know if I had to pay tax because all I know is that you have to pay sales tax but that's if you get is shipped.

You do know that you posted under United Kingdom, not US. But since you talk about dollars and sales tax, sounds like a US question.

Yes you'll have to pay sales tax, if you're in a state that has a sales tax.