How it works? : Tax Free Shopping

Hello everyone, i'll be in U.S.A soon and i wonder how the tax free thing works.

For example : if the product is 1500$ -a mac- on the apple's website and lets say that tax is %10 for the location.

Option 1 : i am gonna pay 1500$ and after that i will take 150$ back somehow.

Option 2 : i am gonna pay 1500$ and i will take some part of tax like 75$ or something lower than 150$.

Option 3 : i am gonna pay 1500$ + 150$ on store and take my extra 150$ back and total price will be 1500$.

Location will probably be Washington. Thanks for answers.