- Storage: Many of these used PCs won’t come with a hard drive, meaning you’ll have to add one yourself. You have a few choices: you can grab a new 500GB HDD for around $25, though it’ll be a little slow. If you’re efficient with your storage, I’d recommend buying a lower-capacity, higher-speed SSD like this 128GB PNY model for $20. Or, if you have enough money, get one of each: use the SSD for your boot drive, your spinning drive for your files, and live your best life. If you find a tower that does come with storage, make sure to test its health with CrystalDiskInfo—if it’s starting to fail, see if you can negotiate the price down further to make up for the drive you’ll have to buy.
- An operating system: You’ll need a 5GB flash drive to install Windows—if you don’t have one, borrow one (you’ll only need it for an hour or two). Almost all of these PCs should come with Windows licenses in the form of a 25-digit key printed on a sticker somewhere on the tower. If yours doesn’t have a Windows license, it’s probably not worth buying, since Windows costs about $100 on its own. If you plan on running Linux instead, you won’t need to worry about this, but since most people will probably want Windows for gaming, make sure it has that sticker.
- A keyboard, mouse, and monitor: As with most PC building guides, we’re only focusing on the tower itself here—we’re assuming you have an old monitor, keyboard, and mouse lying around. But if you don’t, you can often find old office peripherals in the same e-waste centers and classified apps where you found the tower (you’ll just need to budget for them). There are also plenty of affordable “gaming” mice and keyboards on Amazon, from brands like Velocifire and Redragon, if you’re willing to spend a bit more.
- A network connection: My machine didn’t have Wi-Fi, which was fine since I planned on using the more reliable Ethernet connection to access the internet. If Ethernet isn’t an option for you and your PC doesn’t have Wi-Fi, you’ll want to find a PCI or USB Wi-Fi receiver to access the web, either used or new on Amazon.
- A better power supply: while I found the 295-watt power supply in my Dell Optiplex was adequate for my GTX 750 Ti, it’s definitely borderline. If you can afford a nicer model like this EVGA 450-watt unit, it’s a worthy upgrade. Your system will be more stable since it will have more wattage headroom for your hardware, and you’ll have a wider choice in graphics cards, since it has a 6-pin connector.
- Some extra RAM: If your office PC only comes with 4GB of RAM, you’ll be able to get by, but it’s really at the edge of what I’d recommend on a Windows system today. Luckily, those old PCs use the older DDR3 standard, which means you can probably buy another 4GB for $10 (or less) on the used market. You’ll be glad you did, particularly if you plan on opening a lot of browser tabs or playing higher-end games.