Exegesis:

antallagma tēs psuchēs autou ‘as an exchange for his life.’

antallagma (only here in Mark) ‘purchasing price,’ ‘exchange.’ The answer to this rhetorical question is that there is nothing which a man can give to compensate for the loss of his psuchē ‘(real) life,’ i.e. the loss of his very self. Cf. Lagrange: “a life which is his true life, his soul, himself.”

Translation:

Give in return for is in some languages equivalent to ‘pay as a price for keeping’ or ‘pay to get back,’ or ‘pay in exchange for.’

Life should be translated the same in this verse as in 8.36.

Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on the Gospel of Mark. (UBS Handbook Series). New York: UBS, 1961. For this and other handbooks for translators see here .