If you own either the Samsung Galaxy S4 or the Samsung Galaxy Note 2, then you can unlock your handset without having to pay out a penny. This could also work with other handsets.
For instance if you own a device that is with Verizon then you can only use that handset with that carrier. If you go ahead and unlock it however then you are able to use it with any carrier and you can also use it anywhere in the world. You could even send the device to a friend overseas. So if you want to go ahead and unlock your handset follow the steps below.
First put any SIM card that is not your own into the device and then turn it off and back on again.
Enter this code into your dial pad: *#197328640#. Go to main menu >  UMTS >  Debug Screen >  Phone Control >  Network Lock > Options Perso SHA256 OFF > then wait a minute or so, before heading into menus and choosing back. You should then see ‘Network Lock’ – so you choose  NW Lock NV Data INITIALLIZ.
The right sequence should read: Asterisk Pound One Nine Seven Three Two Eight Six Four Zero Pound. Be aware that some people call the asterisk the ‘star’, and the pound ‘hash’.
Your handset should now be unlocked and you should be able to use it with any carrier. As the code has been used for some time it could work with other devices of Samsung, so go ahead and try it.