The easiest way to unlock a Samsung phone for free is to request an unlock from the cellular service provider associated with the phone. However, many cellular carriers have restrictions on who can unlock phones from their service that may prevent some customers from unlocking their Samsung phone.
While unlocking phones from a specific cellular network was illegal until 2014, as of the beginning of 2015 cellular carriers are legally required to unlock phones upon a customer's request. In most cases, customers can request an unlock for their Samsung phone by contacting the associated cellular provider's customer service department. The customer service department then provides an unlock code for the phone after reviewing the request.
Cellular service providers often place conditions on the provision of unlock codes that vary widely from provider to provider. For example, Verizon Wireless currently sells almost all of its phones without locking them to the Verizion cellular network beforehand, with the exception of some prepaid phones that must be used for 12 months with Verizon before the company provides unlock codes for them. In contrast, AT&T has a long list of requirements that customers must meet before the company unlocks their phones, including completion of all the terms of any service contract associated with the phone.