Prebuilt under 500-600 dollars

Title states it.

I'm looking for a prebuilt that can run something like Fallout 4 while still being able to run a few medium/lightweight mods. I definitely don't need it to go 60 fps all the time. I'm really not computer savvy and any other factors just confuse me, which is why I'd prefer a prebuilt. My budget is 600 dollars.

There are plenty of crappy computers for 500-600$ pre built at Amazon but I wouldn't touch those if I was you, make an effort and build one for yourself - it's not hard at all, all you need to do is to follow guides on YouTube or Google - that's it, my first build took me about 2-3 hours but at least I got it working.

For 500-600$ on prebuilt you'll get FX4300 and GTX750Ti at most, while if you decide to build one you can get i3 or i5 with same GPU or even better one.

Here is a refurbished desktop with an i5 4460, 8gb of ram, 1 tb hdd and GTX 760 for $410. Its a start

LINK

I would buy this immediately (great price and the specs are good for 1080p gaming)

Very surprised to see an i5 with a decent graphics card for that price

Remember these tips.
If the seller advertises the CPU speed over 10ghz they are lying to you.
Here's another tip for getting a 1440p/4k monitor for cheap. Just buy a 1080p monitor and then use DSR to unlock the 2K/4K resolutions. This works best on a monitor size >24 inches.

DSR is not same as native 1440p/4k, it's rendered at that resolution then downscaled to monitors resolution, it's improved quality but still downscaled.