When purchasing an apple product, is the price including tax?

Prices in the USA will depend on the store you go to, or the USA street shipping address for online orders. In the USA, you may encounter State sales tax, county sales tax and city sales tax, or any combination of the three depending on where you’re shopping. Those will be added to the listed price and are not included in it.

In the USA, states and local governments control commerce and commerce taxes in their sate, count or city, not the federal government (the nature of a Republic). So there is no unified national sales tax system as found in other countries.