What is the amount to be paid to a non-profit volunteer restaurant – which feeds those unable to pay for their meal – to feed ten indigent persons as expiation for a vow to abandon a sin that was committed?

A vow to abandon a sin is considered a vow of obedience, and according to the preferred opinion, it does not require expiation. However, if the one who made the vow wishes to offer expiation to avoid scholarly disagreement, the method of feeding the poor as described by the questioner is not sufficient according to the majority of scholars, even though some scholars permit it.