Do you want to get a computer whose size is only finger length and only cost 5 dollars? You are not dreaming, Raspberry Pi zero is such a board. It can realize most functions of Raspberry pi but looks smaller ,weights lighter and costs lower.
For this miniature board, we have released 2 versions Raspberry Pi Zero and Raspberry Pi Zero W. Raspberry Pi Zero W support wi-fi and blue tooth communication while Raspberry Pi Zero doesn’t have those functions. So you can choose your board for your own demand.