Rebbi says; "nefesh for nefesh": Money is intended. You say "money," but perhaps "life" (literally) is intended? It follows inductively, viz.: "imposed" ("yashith") is written here (Ibid. 23) and "imposed" ("yushath") is written elsewhere (Ibid. 30). Just as there monetary payment (is indicated); here, too, monetary payment (is intended).