The reason why small bandit is expensive is because of the depth they are caught.
Adult bandits are found shallower, some as shallow as 20 to 30m.
But baby bandits can occur as deep as 70m and they are rarely found at any depth above 30m although at certain seasons they can be occasionally found shallow.
The depth at which baby bandits are found usually requires the use of diving rebreather which is a risky n expensive.
As such usually when baby bandits are caught, they are sold between $2000 to $2500.
In hk, larger bandits are favoured because hk reefers prefer bigger angels.
Whereas in japan, smaller bandits are in higher demand due to their smaller setups.
Personally i would go for a medium small specimen 2" to 3" which is most hardy and requires lesser feeding.
However at this size it would cost around $1200 to $1600 which is still quite expensive.
Adult bandits are cheap but they are hard to decompress and ship and usually perish very quickly in captivity.