Disclosed are systems, devices and methods for providing solar lighting and power to a customer by using pay-as-you-go (PAYG) technology. The PAYG technology allows a customer to make incremental payments for a solar energy system that includes a lighting unit. The payments can be made through a smartphone. A cable is used to connect an audio jack of the smartphone and a PV power jack of the lighting unit. Analog AC signals including data about activation, payment, usage and status are transmitted over the cable between the service provider and lighting unit, through a smartphone. The power jack of the lighting unit is also used to connect to a solar panel of a charging unit and a battery of the lighting unit.