So what is the real fee for application of a TN Visa?

If you’re crossing by air such as New York’s JFK, Vancouver’s YVR, etc, it is $50USD.

If you’re crossing by land (or sea) such as Point Roberts WA, Champlain NY, Buffalo and Fort Erie Bridge, etc. it will be $50USD + $6USD = $56USD.

That’s it?!  Yup.  It is generally recommended to bring cash if you’re crossing the border.

If the application is filed by mail, it is $325.