There are a lot of cheap Arduino UNO and NANO knockoffs and the tech is so stupidly simple (and ancient) it doesn’t take much to design your own (you can put together the most of the hw on a breadboard as long as you get an extrenal USB-Serial adaptor module, and those are also cheap as chips)
For the more modern and powerful stuff at that end of the computing power (i.e. the low, low, oh-so-low end) the simplest option is an ESP8266 or ESP32, which you can get as a module for about $3 - $5 or as a board for about 2x to 3x the price.
That said, this stuff are microcontrollers, not microprocessors, and they’re nowhere in the same range as SBCs like the Pi, so I wouldn’t advise using one of those if what you want is something that can run Linux and use displays with more resolution than 128x80.
There are a lot of cheap Arduino UNO and NANO knockoffs and the tech is so stupidly simple (and ancient) it doesn’t take much to design your own (you can put together the most of the hw on a breadboard as long as you get an extrenal USB-Serial adaptor module, and those are also cheap as chips)
For the more modern and powerful stuff at that end of the computing power (i.e. the low, low, oh-so-low end) the simplest option is an ESP8266 or ESP32, which you can get as a module for about $3 - $5 or as a board for about 2x to 3x the price.
That said, this stuff are microcontrollers, not microprocessors, and they’re nowhere in the same range as SBCs like the Pi, so I wouldn’t advise using one of those if what you want is something that can run Linux and use displays with more resolution than 128x80.