Raspberry pi is a computer which can easily run on linux os uses: can be used as a controller for projects controller meaning send and receive data using raspberry pi to devices for testing. can be used for developing prototypes. simply buy and start exploring the world simple as that. https://www.raspberrypi.org/products/ if your are interested in LINUX install in pi and use as a desktop computer. https://ubuntu.com/download/raspberry-pi https://ubuntu.com/download/iot Buy the latest raspberry -5 Select your country and reseller to buy directly from the reseller. https://www.raspberrypi.com/products/raspberry-pi-5/ Raspberry keyboard can be bought but my experience with the keyboard was boring and some keys were not working It’s better to use other keyboards rather than this. buy the new raspberry with higher configuration 8 Gb/quad core enjoy - https://www.raspberrypi.com/products/raspberry-pi-400/