Tracing a phone number costs about $4 on average as of 2015. Numbers can sometimes be traced for free with assistance from a phone company and local police, but some phone companies charge a small fee. A mobile app called TrapCall charges $3.95 to $19.95 per month for tracing services.
Phone companies use a technology called Call Trace to help customers forward harassing phone call data to authorities. Call Trace is already enabled for some customers, but others need to request enabling, which may or may not be free. After that, customers might be charged a monthly fee or a per-trace fee.
Phone companies' tracing fees vary with their geographic markets. Verizon phones are equipped with Call Trace, and customers are charged about $3.50 to $4.50 per trace. CenturyLink accounts are also automatically enabled, and the company charges up to $10 per trace.
The TrapCall mobile app offers three levels of phone tracing services. With a two-year commitment, its simplest plan costs $3.71 per month. The most powerful plan, which includes audio recording, costs $18.71 per month.