I think equating dollars to lives is too utilitarian a take to be useful IMHO. The goal of charity could be so much more than "lives saved (globally)". It could also be "lives improved (locally)" which cascades into "societies improved (locally)" which further cascades until the effects of local acts of love are far reaching and impact cities, state, and countries.

If you don't know an individual who needs the $1000, then sure, donate to charity. But not all charity has to be in the form of large cash gifts and not all charity recipients have to be cancer patients on the verge of death. Sometimes being charitable to individuals is as simple as taking out a coworker or neighbor to lunch and just talking to them. Lots of people suffer from loneliness, depression, and things other than cancer and would benefit enormously from someone going out of their way and showing an act of love to them.