GiveDirectly is a US based organization which electronically transfers money to poor households in Kenya and Uganda. These countries are serviced specifically because they contain large populations of individuals living in poverty who still have access to mobile money transfer services. Donations are made at givedirectly.org, moved from their US based bank to their electronic payments account, and transferred to the poor. This simple system and low overhead ensures that about 90 cents of every donated dollar makes it to the hands of the poor(90 cents in Kenya, 87 cents in Uganda), who commonly live on less than 65 cents a day. Recipient households are given $1,000 over the course of a year or two and often use the donated money to provide basic necessities as well as to fund longer term investments like livestock and education which yield long term financial benefits as well as increases in food security and mental health. GiveDirectly's system has proven so effective and efficient that, as of late 2014, GiveWell lists them as their top charity.
For an accessible summary of cash transfers and GiveDirectly, see Charity Science.