This post is not a comprehensive dive into the world of microcontrollers, but rather a brief introduction and a compilation of interesting facts I've collected over the months working on a couple projects that made use of contemporary microcontrollers to achieve real and practical goals.
I'm sure you're well aware of the situation with microelectronics prices. It's been getting worse for a couple years and doesn't look like it will improve any time soon due to the on-going crisis in several areas at once: semi-conductor component shortages, logistics issues, political games, socioeconomic factors and everything in between. For an average technically-minded person this means that one must look for creative ways to achieve their goals or alter those altogether.
We do live in the real world after all, and one must adapt or perish.
Remember "low-cost single-board PCs" we eagerly watched evolve and get cheaper over the years? All of those Raspberry/Orange/Rock Pi's and "Zeros", Tinker boards and Jetson Nanos? Oh they did evolve all right… Into overpriced 100+ USD boards. So now we're stuck in a reality where even the simplest single-board ARM PC in the form of a Pi Zero W is valued at 100 USD instead of expected $15-20.
There are practical alternatives to single-board PCs:
The first option is blatantly obvious if you're looking for a device with a real multitasking OS and a load of compute power. And used PCs nowadays? They are cheap. For a market price of about $150 for a Raspberry Pi 4 with 4GB RAM you can get a used mini-PC with a 4-core Pentium/Celeron CPU, 4 to 8 gigs of extendable RAM and a 128GB+ SSD system drive with an option of connecting a second drive via SATA or M.2.
Almost any PC will blow a Pi out of the water performance-wise. Sure, small PCs can't beat Pi boards' dimensions, power consumption and embedded IO-capabilities with over 20 I/O pins exposed for communicating with external devices. So if you're looking to set up a home web/file server, retro emulation station or use the machine as a simple desktop PC, opting for a used mini-PC today would be a no-brainer.
But what if you actually require rich I/O capabilities, small dimensions and low power-drain of a small single-board device?