One breakthrough solution that will change the future of money, and change how people earn and save money, is the combination of micro-tasks that can be done on mobile devices using SMS, micro-payments, and the ability to use a mobile to receive and access funds.
Mobiles are huge. The cellular network is larger than the electrical grid -- there are more places in the world where you can use a cell phone than there are places where you can charge it up. Portable, solar powered cell towers extend the network to places where you would never expect to find it. Rugged, inexpensive mobiles make it feasible for people who could never own a computer to own a mobile phone. For people in very impoverished communities or very remote locations, it can be impossible to find work. Saving is difficult, too; if you do a job that earns you $20, but you only spend $2 a day, how do you safely store the other $18 until you need it?
Crowdsourced work that can be done on mobiles, and payments that can be made through those same mobiles, is one answer. In Kenya, a project called Txteagle matches people with small, bite-sized bits of work that can be done through text messaging, like translating things from one language to another. People sign up for work on the mobile, do the work on the mobile, get paid for the work on the mobile, and can store their savings on the mobile for later use.
I wrote this myself, but here are the references I used: