Hi,
I add two more alternatives:
raspberry is cheaper than arduino
picaxe sell microcontrollers
I suppose that before arduino existed you should buy a microcontroller, and programme it. Arduino allows you change the bootloader, change the function of the chip. But others does not, you have to work with it and you can't change it.
Please, if I am wrong I would appreciate if you tell to me.
thanks everyone,
greetings!