Any person purchasing a vehicle in the State of Ohio must be at least 18 years of age. No person under the age of 18 years can purchase or sell a vehicle in Ohio without a parent, legal guardian, or other person that has legal custody. A contract to purchase a vehicle signed by anyone younger than 18 years old is invalid and may be voided. If you sold a vehicle to a minor they could release themselves from the sales contract, return the vehicle, and recover the vehicle purchase price paid, even though the vehicle has been used, wrecked, and deteriorated in value.
If you say for example sell a 16 year old a motorcycle the 16 year old could drive the motorcycle down the street and wreck the motorcycle. The 16 year old could then bring the wrecked motorcycle back to your dealership and demand his money back because he was not old enough to sign a legally binding contract in the State of Ohio. It is very possible you would have to take back the now worthless motorcycle and return the 16 year old's money.
When a person is purchasing a vehicle for someone
under the age of 18 be sure to compete the form BMV 3751
Minor Consent Form.