Just went onto cellunlocker to see how much to unlock with their generated code. They now have a new disclaimer. The following is taken from cellunlocker's site.
PLEASE READ THIS DISCLAIMER: If you have a Samsung Galaxy S3, S4, Note 2, Note 3 or your Android version is Android 4.4 (KITKAT)
All SAMSUNG devices manufactured after the date of JULY 2013 and Samsung devices running on Android version is Android 4.4 (KITKAT) are subject to REGION LOCKING
If your phone has been used previously with the original carrier, this will not apply to you. However, if your device is BRAND NEW, your must activate it with the original carrier.
If your Samsung device becomes Region locked, you will not be able to fully factory Unlock your Samsung devices so it can be used internationally. Even the correct code will not work anymore.
In order for your Samsung device NOT to be region locked, you MUST activate (FIRST USE) your S3, S4, NOTE 2, NOTE 3 with your ORIGINAL carrier at least ONCE to take your region lock OFF. After your Region lock is off, you can Sim Unlock your device via Unlock Code.
*All Canadian Carriers are NOT subject to Region Locking
*All USA and European Carriers ARE subject to Region Locking
So, activate on your carrier first. Then unlock and use a prepaid sim!!!
It was a quote of $30 to unlock the Mega