How much does it costs to check a guitar on a domestic flight?

Question

I want to bring my martin acoustic but It won't in an overhead bin....

Answer 1

You can check it as part of your checked bag allowance.  It counts as one piece.  If you are only allowed one piece and are already checking luggage then they will charge you based on how much it weighs.  Each airline is different but they generally charge a few dollars per kg.