You probably got that idea because they say it's free to register if taking the course online... There will be a fee after all is completed and before you receive the certificate and card...
Once you pass the final exam and go to print your certificate, the fee will be $19.50... Son just completed the online course and he got his permanent card in the mail maybe 10 days after paying...
Have no clue what the fee is if taking the course in person.