There are reverse phone search websites who claim to offer the services for free. However, as per law, cell phone numbers are private properties of their owners, and thus cannot be publicly displayed or given away. Thus, the information they provide are usually old and irrelevant. They can never be used in the court, as the information is not even legal. Thus, it is much better to use paid reverse phone search services from a known and a legit company, rather than lose your case just to save a few dollars.