Ipod nano 1st generation replacement program costs?

Regarding the ipod nano 1st generation replacement program I wanted to ask if there is any costs to sending it in and getting a replacement? I got an email back from Apple saying they will send shipping materials within two working days. But I also read the Apple Repair Terms and Conditions and it seems like there could be costs given by Apple but its not clearly stated. Any advice/information given would be great since it seems this replacement program has been running for a long time so there should be some information feedback coming from customer who have gone through the process before.

Thanks 🙂