It seems people more often than not someone forgets to tell you about the exit taxes due before leaving Costa Rica until you get to the counter after standing in the long long lines. To save yourself that frustration, know that you must pay these taxes BEFORE you get in that long line for the ticket counter.
When you enter the airport, to your direct left or right you will find branches of the bank that serves the airport. Go to one of these banks and pay your $26.00 exit tax then and only then are you ready to stand in the long line.
Will save yourself a lot of frustration and time by going to the bank first.