SomēI dunno why but I'm into the small embedded boards/platforms. Arduino? Nah, I'll take the ATTINY thank you. ESP32? The esp01s looks cuter to me. STM32 nucleo? Blue pill looks nicer.
I think the appeal is that the size corresponds with the price tag. Though not always the case, smaller stuff == cheaper.
My first set was an Elegoo Arduino Uno Super Starter Kit I got second hand for 25€. A mega good deal considering that the real deal costs, just the board alone, 20€. Some of the parts in the kit sucked though.
Then I got the esp32c3 super mini for 1,07€. If anyone wants to start out with microcontrollers, it's the board I recommend. The Arduino IDE supports it and it works out of the box. I think it's 60 cents more if you want the pins pre-soldered.
I don't recommend atmega stuff! For what they are, they're not as cheap as the alternatives. For example, an attiny85 costs between 2-3,5€. The stm8s001 costs less than 1€ a piece and has 2x the clock speed, 2x the RAM and 2 16-bit timers, which is 2 more than the ATTINY, which has none.