people charge phones on daily basis O.o 70 naira is like 16 cents. thats 58.4 € per year. but a normal solar plate with usb plug for phone charging is only 22€
https://smile.amazon.de/Ladeger%C3%A4t-tragbares-USB-Ger%C3%A4te-Outdoor-Klettern/dp/B071Z1LGFV/ref=sr_1_27?__mk_de_DE=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=solar+phone+charger&qid=1588415306&sr=8-27
arent solar plates cheaper? they have become quite cheap in the recent years...