The MiSTer is an open-source project that emulates consoles, computers and arcade boards via FPGA. Setup and use has gotten really simple, so I created a quick video that will get you up and running as quickly as possible, on the lowest budget possible! All links to everything you’d need are in the main MiSTer page here:
MiSTer: https://www.retrorgb.com/mister.html
If you’d prefer a deep-dive video, I strongly recommend checking out My Life In Gaming’s resent 2+ hour, magnum opus MiSTer video. I actually think both compliment each other well and if you’re new to the MiSTer scene, you’ll want to watch both: