Raspberry Pi 3

After connectiong to your monitor this can be used as a desktop computer doing word editing to spreadsheet work to presentation making and can browse internet watch youtube videos and listen to music.
IDEs for Various programming languages are inbuilt like JAVA, Python, Scratch for small children.
Great computer learning tool for small children.
This can be used to develop small large scale projects infact this has been to the space taking photos and sending back images to control room. By combining this can make relatively high power servers for LAN and WAN software systems like (Accounting SW, CRM, Payroll etc).

✔ 1.2GHz Quod-core CPU
✔ GPU: Broadcom VideoCore IV
✔ Inbuilt WI-FI adapter
✔ Inbuilt Bluetooth adapter
✔ Storage: microSD(supports from 8GB SD cards to 64GB)
✔ Ports: HDMI, 3.5mm analogue audio-video jack, 4×USB 2.0, Ethernet
✔ Camera Serial Interface (CSI), Display Serial Interface (DSI)
✔ GPIO: 40-pin header, populated