The amount of sales tax paid for a newly purchased vehicle is determined by two factors. The first is the amount that the owner paid for the vehicle and the second is the sales tax rate in the county the vehicle was purchased. The maximum allowable sales tax rate is 15% of the vehicle's assessed value. Private party and used vehicle sales may be taxed according to their Standard Presumptive Value which is based on the vehicle's appraised value. Current laws allow for any sales tax paid on a vehicle to be used as a deduction when filing tax returns. Up to 70% of the sales tax amount can be deducted from a tax return