I have a Milk-V Duo with an Sophogo SG200X processor that is wire bonded to an in-package 512 MB RAM die (called System-In-Package or SIP) that can run a pretty usable headless Linux on what's probably a $1 processor, in bulk. The Pine64 Oz64 also uses an SG200X processor.
I originally picked it up for an MP3 player project, but ended up using an ESP32-C3. Instead, I'm going to install Ageless Linux and set it up as a "minimum viable violation": https://agelesslinux.org/hardware.html. I already have the rest of the parts and just need to wait for a release to try it out.
