If you're itemizing, you get to choose between deducting your state and local income taxes or your state and local sales taxes. You can't claim both and you can't claim either one if you're taking the Standard Deduction.
If you go with the sales tax deduction, you can claim the sales taxes you paid on just about anything you bought, whether it was purchased online or locally, in-state or out-of-state, big or small.
However, for tax years 2018 through 2025, the SALT deduction (which includes sales tax) is capped at $10,000. That means if the combined total of your sales tax, real estate tax, and personal property tax amounts to $15,000, you can only deduct $10,000 maximum.
