The Samsung Galaxy S4 along with the S3 are both great devices and both are very powerful. Due to this many people have them today. Some bought devices that were locked but now they can be unlocked thanks to a leaked unlock code that is going around.
You can use the leaked unlock code for the Samsung Galaxy S4 and S3 from your home.
To begin you should put a new SIM card into the device and then turn the handset back on. When the device is on you can open the dial pad and then type in the leaked code which is, *#197328640#. You should then check out the steps below.
 UMTS >  Debug Screen >  Phone Control >  Network Lock > Options  Perso SHA256 OFF.
You should now wait for 30 seconds and then head back to the main menu and you should now see Network Lock. You can then choose NW Lock NV Data INITIALLIZ and your device should be unlocked.
While the code is said to work with the Samsung Galaxy S4 and the S3 you may also be able to unlock other devices belonging to Samsung too.