Can you trade a 2nd generation iPod touch in for a 3rd generation iPod touch?
Yea but instead of getting a third generation you should get a fourth gen instead. You can trade in an buy used iPods at GameStop. That's where i got my fourth gen and its worth it. Just make sure the screen isnt scratched.
You can trade a 2nd generation iPod Touch for a 3rd generation iPod Touch. However, you may need to consider its features and if it's convenient for you with what you intend to use it for.