Welcome to the Apple Support Communities. I was reading about your issues, there are a few things that can be done in the following article for troubleshooting hardware.
If you are still having the issue, the answer to question about price is on the service answer Center for iPod.
You can also look to see if there was a warranty associated with the iPod if it was just replaced.
If you choose the route for Apple to service you iPod Nano, below is the link to choose the store closest to you and then you will be able to pick the time the is the most convenient for you.
Have a great day,