Unreal Engine 4 is now available to everyone for free, and all future updates will also be free! You can download the engine and use it for everything from game development, education, architecture, and visualization to VR, film and animation. Enjoy :)
For developing with UE4, we recommend a desktop PC with Windows 7 64-bit or a Mac with Mac OS X 10.9.2 or later, 8 GB RAM and a quad-core Intel or AMD processor, and a DX11 compatible video card. UE4 will run on desktops and laptops below these recommendations, but performance may be limited.
This is awesome!