In Africa they've had this since ~2005 with the Mpesa system. It basically transfers cellphone credits as payment. In certain regions everyone with a dumb phone was hooked up and you could do anything from buy a coconut from a guy on the side of the road to pay your taxi driver to pay at the supermarket.
Wow, this is a great reply! "In Africa" -> Can you share a few countries? Google tells me that East Africa is the biggest users: Kenya, Tanzania, etc. (No hate on the use of "In Africa here"... as Google tells me it is used in at least 10 different African countries.)
