If you are in the U.S., then it would be the shipping cost to us. The repair itself would be under warranty, which also includes return shipping.
If you are outside the U.S., then shipping both ways is covered by the customer, as is any cross border charges. The repair itself would still be covered under the warranty.
If you are not in the U.S. or Canada, you should contact customer service to see what the best method of returning for repair would be.
For our full repair information, please visit this link:
http://www.paulcbuff.com/repair.php