https://news.ycombinator.com/item?id=9664983
jbniche points out: "Just think the impact that would have had if it had been divided up and given directly to each Haitian adult. The adult population of Haiti is roughly 6 million, so we're talking about almost $100 per adult Haitian. Roughly, it's about 1/8 of the per capita GDP of Haiti. Imagine what you could if you were a poor American and received 1/8 of the American per capita GDP after a disaster (~6000 USD). That's a new roof, or a replacement vehicle, etc. It's not life changing, but it would have been very significant, and massive in scale."
https://news.ycombinator.com/item?id=9666390
and the article supports his point, saying that "A 2013 study in Uganda found that people who received cash enjoyed a 49 percent earnings boost after two years, and a 41 percent increase after four years, compared to people who hadn't gotten a transfer. Another study in Sri Lanka found rates of return averaging 80 percent after five years. In Uganda, not only were the cash recipients better off, but their number of hours worked and labor productivity actually increased."
But for smaller amounts (like the U$ 100 proposed), "One program gave $200 to at-risk Liberian men who were either homeless or who made their income from dealing drugs or stealing. The lead researcher, Chris Blattman, summarized the findings in an op-ed in The New York Times:
"Almost no men wasted [the money]. In the months after they got the cash, most dressed, ate and lived better. Unlike the Ugandans, however, whose new businesses kept growing, the Liberian men were back where they started a year later. Two hundred dollars was not enough to turn them into businessmen. But it brought them a better life for a while, which is the fundamental goal of any welfare program. We also tested a counseling program to reduce crime and violence. It worked a little on its own, but had the largest impact when combined with cash.""