It has been awhile but I believe the fee was $200 per year for Ameritrade which I use for mainly (some exceptions) my lower priced stocks and I had to complete most of the form. When I sent it was a book since I had a few monthly payers. What is really funny they stopped taking out the withholding on those stocks after I went through the process using the NR7-R.

I don't know about the other brokers.