Somewhere on Youtube is a talk about the washing-machine barrier. Most of the world's women still have to wash clothes by hand, which can take several hours a day of hard labor. That's the big leap that revolutionizes the world for most people. So if they get a $20 tablet, they should look up washing machines.
This is somewhat related to my posts on drinkable water, and the time it takes for the poor to find and acquire water, plus man-hours lost to disease that could be spent working, making a living and improving quality of life. The Slingshot is a real solution to the problem: