Best Buy’s got a Raspberry Pi 4 2GB with CanaKit heat sinks and power supply for just $39.99. Add a cheap MicroSDHC card and a solid USB controller or two to be well on your way to setting up a RetroPie retro game system. Sure, a Raspberry Pi will do all sorts of other actual computer and controller stuff, but why would you want to do any of that when you can have a multitude of retro and arcade games available on demand?
I’ve personally set up RetroPie and then crammed it into an arcade cabinet. It remains as one of my all-time favorite DIY projects, so hit me up if you have any questions.