There are no free services that provide you with sensitive details of a vehicle’s license plate details; as such information is prone to security threat if available on the public sector. You are not going to come across services that offer look up license plate free tags to any of their search listings, for this very reason. The only authorities who can search for license plates legally are the police and the DMV of a state. Special websites that are authorized to conduct license plate searches demand a nominal fee for their services, as compared to a private investigating agency.