Before spending any money, you must attempt the legal, free route. US carriers are required by the FCC to unlock devices under specific conditions (though the rules are loosening, MVNOs have strict policies).
If the device was reset without removing the Google account first, it will be "FRP locked."
You will need to provide your 15-digit IMEI and the original network.
Even after following the steps, you might hit a wall. Here is why: