Basics

The Newest Raspberry Pi
Has 1x USB Type C, 2x USB 3.0 type A, 2x USB 2.0 Type A, 2x Micro HDMI, A DC In Jack, and a Pinout
Either 1,2,or 4 GB RAM
A Good Review on the Raspberry Pi 4 Albeit a Bit outdated
Supposedly Capable of two 4k 30FPS Displays or one 4k 60FPS Display, although user experiences may vary
~$45.99 for the 1GB RAM Model (All costs according to the amazon link in the "Useful Links" Section
~$48.01 for the 2GB RAM Model
~$62.00 for the 4GB RAM Model

Installing OS