Latest ESP32 S31 can runs MMU Linux amd support an Ethernet port and other wireless systems [1].

The board mentioned in the post is like a barebone mini RPi that cost only USD$20, a fraction of the cost for normal RPi.

A more complete embedded system with the same ESP32 cost a real bargain at USD$80 incorporating sensors, display, etc [2].

[1] The ESP32 S31 Runs Linux:

https://www.i-programmer.info/news/91-hardware/19197-the-esp...

[2] ESP-Mosaico centers dual-core RISC-V ESP32-S31 around a 2.16-inch square AMOLED:

https://linuxgizmos.com/updated-esp-mosaico-centers-dual-cor...