I just double checked, and I paid for returning mine. But mine was out of Kobo's warranty, though still under store warranty, and the store was going to replace it with a different brand. I'd originally reached out to Kobo to see if it was possible to repair myself (it had a software problem). So I thought Kobo was being generous when they offered to replace it (and they gave me a glo instead of the touch that I had, upgrade!).
So I didn't mind putting it in a small box with some bubble wrap and paying to ship it to a processing center nearby. It cost me about what a latte would. They'd gone above and beyond for me.