Sales tax on a car is an itemized deduction. Unless all of your itemized deductions add up to more than the standard deduction for your filing status, you will not get a tax break for the sales tax deduction. Itemized deductions include mortgage interest, medical expenses more than 7.5% of your AGI, sales or state income taxes and property taxes up to $10,000 total, and gifts to charity. They are reported on Schedule A.
