Emulation System Requirements
Emulation on PCs
Special note: older emulators and Windows games may require the old DirectX End User Runtime to work, but they won't necessarily prompt you for it ... it's not a bad idea to just install this right off on Windows systems
Basic Emulation (Price Range $50-$300 USD)
The "basic emulation" category consists of the most stripped-down, inexpensive and basic options for getting older emulators running. There are a few general categories here. The absolute cheapest will be your single board micro-computer options like the Raspberry Pi, which you'll need to connect to a monitor or TV to use. This category also includes the lowest end of the "notebook" computer category, the cheapest of which (like Chromebooks) can go as low as $100. It also includes monitor-less mini-desktops which are generally in the $150-200 range new for more power and storage than the other options. And of course you can always just buy an old-ass outdated used laptop or desktop in this price range.
So what can you emulate with these? Expect to go up to the 64-bit generation, but not much beyond that.
Examples include:
Raspberry Pi 4: If you go with a Pi, make sure it has at least two USB ports for use of mouse + gamepad
There are Pi alternatives but they tend to be more expensive. Some are more powerful, but tend to have the added issue of devs abandoning them really quickly. Odroid seems to have the best reputation of the "premium Pi" alternative options.
Notebook PCs:
Mini-Desktops:
Low-End Emulation ($300-$600 USD)
In this price range you'll be looking at lower-end full-size laptops and the most basic desktop gaming rigs. You'll get a lot more bang for your buck if you go with a desktop, but laptops in this price range can handle a lot of fairly recent games at lower graphics settings.
In terms of emulation a desktop in this range will usually handle nearly everything, but the laptops will probably start choking on the bigger games in the 128-bit generation and won't be up for anything beyond that.
Laptops:
Lenovo Thinkpad & Ideapad lines
Acer Aspire series
Prebuilt Desktops:
iBuyPower Arc B
CyberPowerPC Gamer Master
Mid-Range Emulation ($600-1000)
This is another category where desktop dollars will take you farther than laptop dollars, but you can get a quite competent gaming laptop in this price range and it should handle all the emulators you throw at it with good settings (barring some extreme cases).
Laptops:
Dell G3 15 or G5
Lenovo Legion Y545
Asus TUF series
Prebuilt Desktops:
Alienware Aurora line (lower end, these can get expensive)
Lenovo Legion / IdeaCentre line
CyberPowerPC Gamer Extreme
High-End Emulation ($1000+)
This is the category where you're not just comfortably maxing out any emulator you can find, you can also run pretty much any new game with high settings. Expect to pay for the privilege though.
Laptops:
Alienware Area 51 or M17
Prebuilt Desktops:
Corsair Vengeance
Alienware Aurora line
SkyTech Supremacy or Archangel