Yes, you will be charged sales tax, based on what your state's sale tax rate is.
According to Apple:
Tax rate
In accordance with state and local law, your Apple Store purchases will be taxed using the applicable sales tax or sellers use tax rate for your shipping address. If the tax rate changes before your purchase is shipped, the rate in effect at the time your order was received into our system will apply.
If you don't mind not ordering from Apple.com, I don't think Amazon.com charges sales tax.