I started years ago with arduino devices for my diy home projects : 8/16 mhz, some kilobytes memory and lots of analog/digital IO's.
Back then it was about 5 to 10€ a piece (from China...).
One example : i follow my water consumption with an arduino and a sensor (a reed switch to be exact).
Willing to cut the cost down as well as cpu consumption (i use 3.7v 18650 batteries), i moved on to attiny85 mcu's.
A bit more hardcore but so cheap (less than 1€ a piece) and so low on consumption...
All my temp/humidity sensor are based on this lovely mcu.
Then came the esp8266/esp32 generation (wifi builtin) : here again for a few euros, i was amazed with its power/memory/connectivity capacities.
In parallel, I also played with raspberry's which have enabled many diy projects:
-My domotic box is based on a rpi + an open source project (Jeedom
-My video player is based on a rpi (Librelect
-I block Ad's thanks to Adguard
running on a rpi
-My 3d printer is shared over the network thanks to a rpi (octopi
What I meant to say:
I feel myself so lucky to have all these plethoric and cheap offer today from low mcu's costing a few euros to cheap but "true" computer like raspberry's.
Thus, it may be worth to consider what are your needs when you are about to buy such a device : cheap/limited but fast or powerful/exhaustive but complex.
My father bought be an electronic box in the early 80's : it was costy, complex and limited.
Still, i was able to build my own radio (after many days and trials/errors).
Nowadays, the offer is nearly illimited and the only limit is our creativity.
I am telling you guys : i would love to be a 10 years old kid today and have my father take me again on the diy amateur electronic journey again