Make sure you check any local stores that have generous return policies. The local Best Buy had an entire table of discounted "open box" 3G iPods for good prices. They had probably 10-12 iPods discounted and ready to go.
The 20GB 3G models were $229 and I'm sure you could open them to check the condition. I don't recall the prices on the others.
Makes sense, with all the returns for 4G models.
Heck, maybe you'd get lucky and find they forgot to delete their music collection.
B