Cheap Boards w/ Built-In Battery Management?

I have some ESP32's from SparkFun that have built-in battery management. Those were about $20 each.

I'm looking for something more basic (and cheaper) that has an ATMega328 as well as battery management (charge controller).

Any pointers would be appreciated.

Not really cheap but cheaper than $20.

Not really cheap but cheaper than $20.

Adafruit Feather 328P - Atmega328P 3.3V @ 8 MHz : ID 3458 : $12.50 : Adafruit Industries, Unique & fun DIY electronics and kits

Oh that's actually amazing. I very much like the little thru-hole area on the end. Thanks!