GiveDirectly gave about $1,000 (or $1,871 in purchasing power terms) each to more than 10,500 households, through three transfers over the course of about eight months. The program amounted to about 15 percent of the GDP of the local area. For comparison, that’s about three times as much economic stimulus, relative to the size of the economy, as the 2008-09 stimulus packages in the US.
They found that the cash transfers not only benefited recipients; they benefited people in nearby villages too because recipients spent more money, some of which went to their neighbors’ businesses. Contrary to some fears, there were no meaningful inflation effects, and there were no envy or jealousy effects where people close by who didn’t receive cash felt worse off after the intervention.
One of my favorite charities, GiveDirectly, researched the effects of large cash transfers on inflation in Kenya.
Vox has a good write-up: https://www.vox.com/future-perfect/2019/11/25/20973151/givedirectly-basic-income-kenya-study-stimulus
Here’s a direct link to the published study, updated Nov. 2022: https://onlinelibrary.wiley.com/doi/full/10.3982/ECTA17945
If you’re curious, they have info. about many of their research projects (a number of which are published and peer reviewed) at https://www.givedirectly.org/research-at-give-directly/