See the issue here isnt what you paid for it, its what its worth, and $200 for a used nonflu with a SMC, is _way_ too much.
A new nonFLU is $150
A new 128 SMC is about $30
Thats $180 for a NEW set, and your inital asking price is $190-$200 for a USED set, whats wrong with your math? Just because you were stupid enough to pay $70 for a SMC doesnt mean that its worth that much. You can get one for about $30-$35 on almost any webstore (I got one for $26 new)
Note also the GBXs's GP32's are modded, they are not just GP's that can overclock to 166, so if you didnt get a modded GP32 from GBAx you cannot compare the two.