How much should it cost to repair my iPod 3rd Gen?

I've got an iPod 3rd Gen that's starting to show its age. I just want to know if it'll be cheaper to repair my current iPod, or just buy a new one altogether.

I was wondering how much it would cost to repair/replace the follow:

Battery (losing charge quickly)

Battery port (constantly disconnecting, takes forever to charge)

Volume buttons (Not responding)

Headphone jack (not registering left ear)

Optional: Screen (few scratches, nothing too bad)

Thank you