water damage

Apple will exchange your iPod for a refurbished one for $199 for 64 GB 4G and $99 for the ohter 4Gs.. They do not fix yours.

Apple - iPod Repair price

It is under the warranty topic of the link I provided:

My iPod is not eligible for warranty service. What are my service options?

Apple offers two options for iPods that are not eligible for warranty service. You can contact Apple or your Apple Authorized Service Provider for more information.

• iPod Out-of-Warranty Battery Replacement Service: If your iPod requires service only because the battery's ability to hold an electrical charge has diminished, please refer to the Battery Replacement tab on the left for more information.
• Out-of-Warranty Service: If your iPod requires service for any other hardware failure that is determined by Apple to be repairable, Apple will service your iPod for an Out-of-Warranty Repair Service fee. Refer to the Repair Pricing tab on the left for more information.

If Apple determines that an iPod is not repairable, for example, if it has failed due catastrophic damage or the iPod has been disassembled into multiple pieces, then Out-of-Warranty Service is not available and the iPod will be returned. Please see Apple's Repair Terms And Conditions for further details.