No minimum to my knowledge. Lowest TIV for the games I traded was for Castle Shikigami 2 (PS2) - $0.75; they've taken all PS2 and GC games from me so far.
Wow, exact same situation here. Sent my copy away more than a week ago in near-perfect condition and got the same "damaged item-return" status today in their trade-in confirmation e-mail. Smells like some bullcrap right here cause I locked the price in at $41 TIV and traded it 2 days later. I...
Base TIVs for the following traded today (11/20/2010); Some are revised values, others are just up-to-date refreshes for the TIVs currently listed by the OP:
:wii:
Zack & Wiki: Quest for Barbaros' Treasure - $2.00
Sin & Punishment: Star Successor - $ 12.00
Wii MotionPlus Accessory - $6.00...