You do not need to report the purchase of a car (new or used), unless you are using it for business purposes. Commuting to work or school does not qualify as a "business purpose".
If you are itemizing deductions on Schedule A, you may be able to claim a deduction for the sales tax you paid when you bought the car and/or any property tax you pay as part of your annual registration fees.
For more information:
https://ttlc.intuit.com/replies/5711743
