תּלמוד אויף שמות 21:30

Which Tanna holds that it is atonement? R' Hisda said, R' Yishmael, the son of R' Yohanan ben Broka, as it is taught, 'he gave a ransom from his life', that is the money of the victim. [However] R' Yishmael, the son of R' Yohanan son of Broka says, it means the money of the owner. Is it not that the difference here is that one [the Rabbis] explains it is monetary compensation, and the other [R' Yishmael] explains it is an atonement

What is the reasoning of the Rabbis? It is said above, (in a similar case regarding causing miscarriage) value is according to the victim (fetus), so to here value is according to the victim.

Rava said to him, Let the witnesses say if you had, would you be sold? So likewise we should not be sold. Rather R' Hamnuna meant to say If either the accused or the witnesses have, they are not sold, but if neither the accused nor the witnesses have, they are sold. Rava said to him, The Torah states, he is sold for his theft, meaning theft and not conspiring.