I came across this very useful paper on applying the learnings of BE for reducing poverty. It is great to see BE principles being used widely
The paper shows how simple and less costly ideas can lead to more financial inclusion and improving poor participation in social programs.
They have some simple ideas like it isnt enough to ask people to go to a bank and open a no frills account but also give people a proper map with direction to show the location of the bank. Similarly make government transfers go automatically to a bank account (the default should be bank), etc.
For increasing participation in various government programs use simple forms, make it costlier to delay joining of these programs etc.
The best part about all these ideas is that it is pretty low cost and involves very little changes in the actual program.