Wikipedia says: “The Raspberry Pi is a series of small single-board computers developed in the United Kingdom by the Raspberry Pi Foundation to promote the teaching of basic computer science in schools and in developing countries. The original model became far more popular than anticipated, selling outside of its target market for uses such as robotics. Peripherals (including keyboards, mice and cases) are not included with the Raspberry Pi. Some accessories however have been included in several official and unofficial bundles.”
Raspberry Pi is a tiny affordable computer that you can use to learn programming.
Wikipedia also says: “According to the Raspberry Pi Foundation, over 5 million Raspberry Pis have been sold before February 2015, making it the best-selling British computer. By November 2016 they had sold 11 million units.”
If you are thinking of buying a Raspberry Pi computer you need to know that you will need to buy each component separately and assemble it to get a fully functional computer. Have a look at the Raspberry Pi 101 web page for more information. You will need a mainboard to start with. After that you will need the following: a power supply, a case, a micros SD card, a USB keyboard, a USB mouse, an HDMI or VGA adapter.