You save a little electricity by unplugging unused devices but most things when shut off use very little electricity that it hardly makes a dent on your electric bill.
I tried unplugging some devices and electronics that were not in use and found that my electric bill didn't even change any bit whatsoever so it wasn't worth unplugging the devices and electronics.
Cell phone chargers are one of the low electricity users that it barely uses a penny a month to keep them plugged in.
I always just leave my cell phone plugged into the charger when not in use to keep it charged and ready to go.