Sync 3 uses a SD card. While the 2016 is reportably up to date, a new card generally run arouND $150-160.
Pulled this from the Sync 3 update manual "Annual navigation map updates are available for purchase through your dealership, by calling 1-866-462-8837 in the United States and Canada or 01-800-557-5539 in Mexico. You can also visit:"
There is no SD card slot on sync 3. It would have to be a USB or wi-fi update.