Thanks for the question! Keep in mind that this is written from the assumption that you have no/very basic knowledge of older computers, so I apologize if this comes off a bit patronizing! Even if you know quite a bit, other people reading may not and I want to make sure people are knowledgeable before making a purchase!
If you dont care about hardware, and your current pc can handle it, I’d recommend setting up a VM with the operating system of your choice (windows xp would probably have the most flexibility). Look up a tutorial on how to set up a VM with VirtualBox, and you can easily find .iso files of your operating system of choice online. (Obviously be careful of what you download). This is also convenient because if you dont own physical copies of your games it’s pretty easy to get the files from the internet archive and transfer them to the VM! If you need any more help with this, feel free to send me an ask and I can help you out!
If you’re a hardware lover like me though, I definitely understand wanting to have the experience of the real thing! Please keep in mind im not totally educated about specs and technical stuff, so take my opinion with a grain of salt and look for others input as well (followers please add on / correct me)!
A lot of it depends on the kind of games you want to run, if you’re fine with only 2d games you should be fine with most computers that have an appropriate cpu/ram for the year it was made! However, running 3d games will definitely need a good gpu. There are plenty of people on ebay who sell custom built computers geared towards retro gaming, I’d recommend looking into listings of those even if you do not want to buy on eBay just to get an idea of what you would like!
I personally use Facebook marketplace to look for old computers that I want to buy. A lot of times you can get pretty good deals on there! While not a gaming oriented computer, I got my micron millennia, including the crt monitor, keyboard, mouse, and speakers all for $80! It also runs pretty much any games I want to play on there, but I haven’t tried any beefier 3d games yet so I’m not sure how it will do with those. You can also check local thrift stores around you as well, I’ve been able to find a Dell optiplex for $40 once before. I would recommend local shops rather than goodwills since most goodwills usually sell their good stuff online for auction, but it doesn’t hurt to check if you’re feeling lucky!
Keep in mind that buying locally very much depends on if you can drive/have access to a car, so I totally understand if this isn’t an option for you. I also have only ever lived in the US so your buying options will probably be different if you are in another country. If you know of any local retro tech enthusiast groups, they could probably help you out specific to your location! Again, Facebook is a good resource to find local groups.
The other option is buying from eBay. It will be more expensive because of shipping but you can at least get something more geared to your specifics and it’s more convenient if you do not have access to transportation. Searching up something like “custom retro gaming pc” or “vintage gaming pc” should help you out!
Also, if this is your first time buying an old computer, or you do not have any experience with technology repair, you may want to buy from someone who has that experience and has already refurbished the computer for you. Blown capacitors and shitty power supplies are no joke, they can be very dangerous! If you absolutely need a computer that is advertised as not working/not tested, take it to someone who knows what they’re doing before plugging it in. Again, I apologize if this comes off as patronizing but I want to make sure everyone is safe and no one has any bad experiences that may turn away people from this hobby!
Another recommendation I’d give is to get something you like! I know this might be a bit obvious, but I really like windows 98 because of nostalgia reasons, and my roommate would often ask me why I didn’t get a pc with windows XP. Personally all the games I want to play run fine on 98, and i’m willing to use a VM for games that need XP. Get something that makes you happy if it is within your budget and convenient for you!
I apologize if this is a bit rambly! I’m waiting for an oil change and im bored lol. Other people feel free to add on and im willing to answer more questions if needed :)
