If you were issued a warning there should not be any court costs because there will be no conviction. Therefore, call the court and ask if there is a fine for a warning. If not, you are okay and won't have to pay anything. If there is, don't try to go it alone, simply search for a criminal defense attorney here on avvo.com in Charlotte, North Carolina or Concord, North Carolina and ask them to help you by making a call to the officer for you.
There is no fine for a warning in NC. The fine and costs are for the seatbelt violation. This does not give you any insurance or drivers license points. You do have the right to a judge only trial (bench trial), however whether or not the trooper would have given someone else a ticket is not a defense that the judge will recognize. A seatbelt violation is one of the very few charges in NC where it is usually cheaper just to pay the ticket. As an aside, if the trooper had charged you for not having your drivers license, then showing up in court with a drivers license that was valid at the time would be a defense and the charge would have been dismissed.