RetroGaming on The Cheap - RetroPie
Emulation as it is, is sort of lifeless in front of your computer playing retro games isn't the way to go because of the way it is delivered and the too close proximity to the machine in itself. RetroGaming isn't about playing games it's about the whole experience surrounding the playing.
TV, Pad and aspect ratios from another time, are the way to go because they deliver the experience you've had playing all so many years ago. (dang I feel old)
If you're into emulation and you're limited by place and still want to experience a more nostalgic playing way, side for a RetroPie. https://retropie.org.uk/ is your address there as there's detailed documentation on how to set up a system whether it is on a computer using a Debian,Odroid or RaspBerry and all the requirements are listed there.
Namely you can start playing on the cheap there for about $50 however I do recommend to get the budget above 99+ in order to get different kind of pads which would widely contribute to the experience.
For the tech-savvy folks they can get away by using SSH to make the setup of their RetroPie. For the least tech savvy however you can just follow the setup guide ! (RTFM)
On and all, RetroPie remains not only a cost efficient way to setup a multi machine emulation system but a satisfying experience that deliver tons of memories through a very solid emulation. All machines up to the PSX can be successfully ran without any issues beyond that you may experience slightly less glorious performance depending on the machine you're setting up.