Metr helps you simplify your prepaid electricity budget. All you need to do is create an entry each time you purchase electricity and Metr will automatically calculate your cost per unit, daily expenses and daily consumption. These statistics can help you be more aware of your electricity usage, providing a metric for you to improve and save!
Under useful stats, it also has Time Until Next Refill. This can help you budget and plan, knowing when you will need to purchase electricity again. It will also allow you to know how long your balance is going to last.
This is by a brand-new developer as their first attempt at writing an Android app, so it may have some rough edges, but it could be really useful to many in South Africa.
It is free with adverts so although the dev does not collect or share your data, the Google ad system may well do so. If the app does well enough, maybe the dev will consider doing a paid ad-free version too.
See https://play.google.com/store/apps/details?id=app.metr.metr