2.3 On Profit…. And “ONAAH”
When you make a sale to your fellow…do not victimize one another.
Vayikra 25:1
And when you transact a purchase to your friend,
or acquire from the hand of your friend,
you shall not defraud one another.
Vayikra 25:14
Mishnah: Both the vendee and the vendor can claim for over-reaching,
just as the law of over-reaching holds good in the case of a layman,
so, it holds good in the case of a merchant.
R. Judah said: There is no over-reaching for a merchant.
He who was deceived has the upper hand,
if he wishes, he can either say “give me back my money,”
or “return what you over-charged me.”
Bava Metzia, 51 a
A faulty coin should not be passed on to others who might use it for cheating.
A hole should be made in it and given to a child as a necklace.
Baraita Bava Metzia, 52 a