Machankura is a custodial LN wallet that uses USSD, meaning it can be used by any phone, including "candy bar" phones (feature phones) -- which can be obtained brand new for $12 (at the low end).

Also, phone plans are not like in the West. Airtime is generally purchased with "bundles", or plans where you can choose the plan based on how closely it matches your usage.

For instance for $0.15 you can buy 20Mins (outgoing voice) +20Mbs (data), for use for one day. Incoming calls and texts are free, so it isn't even required to buy the plan each day.

Most people with smartphones though are paying $20 to $40 / month, mostly due to social media addiction (only half joking there).

And there's the buy now, pay later model for smartphones, where payment is required daily. Fail to pay, and your phone becomes locked until payment is made.

Overindebted? There's what's essentially an overdraft facility, with steep payday loan rates.

Incidentally, the government of Kenya owns more than a third of the near-monopoly mobile network provider which also owns and operates the mPesa mobile payments network. It's a very profitable business. Mobile subscribers are paying fees coming, and going, while awake and asleep.