They partner with mobile providers, and payments are via mobile phone. One notable feature is that if the panel is stolen, it is disabled. (not sure if it is replaced.) This is a 5-year pay off system, but presumably could be paid for faster.
It just won an Israeli prize
The Lumos PowerSystem contains a solar panel (ten times more capacity than comparable units), and an indoor unit (includes power storing battery, output sockets, lights, and connecting cables).
Thanks, I've added it to the pay-as-you-go solar list: