years ago i found a boxed turbo duo at this one flea market, but it came with no software, perhaps today i found the other half of the haul. either way this score makes me very happy to be a duo owner. all of the following games for $25-

keith courage (of course!)*
exile
monster liar*
gate of thunder
dragon slayer
final zone II*
fighting street
shadow of the beast
Ys III wanderers from Ys
cosmic fantasy
vasteel
blazing lazers*
exile: wicked phenomenon
galaga 90*
ninja spirit*
devils crush*
all complete in the jewel case
*= for trade

oh and i also scored a 5200-2600 adpt. and a 5200 comp pro arcade stick, whoo hoo it pays to look in every pile of CDs