Raspberry Pi 4 is a complete desktop computer for just $35
The Raspberry Pi was originally designed to provide an ultra-cheap way to encourage kids to code, but the uncased credit card sized computer has found an appreciative audience well outside of the education system, going on to sell over a million Pis in its first year alone. Each new iteration of the Pi has added something new, including a 64-bit processor, dual-band 802.11ac Wi-Fi, and Power over Ethernet (PoE) via a HAT.
Source: betanews.com