More RAM and the fastest CPU you can afford is recommended.
It's really difficult to recommend a "get by" computer that will run Lightroom. People will purchase what they expect will be the most outstanding performing computer possible, and Lightroom will literally crawl at a snail's pace. It seems that every computer performs differently. It would be difficult to predict what any computer will do. The only thing you can do is purchase the computer that you feel will meet your needs and then hope that Lightroom will do what you expect it will do. I'm running a six year old HP computer that has been upgraded from Windows 7, I'm now running Windows 10. It will only accommodate 8 GB RAM. It performs adequately for me. Others have purchased computers with 64 GB of RAM and the fastest motherboard they can get, expecting Lightroom to run lightning fast. But it hardly will perform at all and sometimes won't. So you'll just have to give it a try and see what happens. I would recommend a i7 processor and 8 GB RAM, but that is just my own personal bias. I would have more RAM is my motherboard would accommodate it. Good luck.
In this case, do not get anything bigger than a 1920x1080 monitor.
My desktop PC is five years old. At the time I built it, I think it qualified as "high-end." Now it certainly isn't. In spite of its age, it runs LR Classic CC 7.2 perfectly--fast, smooth transitions from image to image and from module to module.
I am adding this to the discussion because it might make sense for you to find an older, used PC with the right specs. As others have pointed out, and you will read in this forum, having enough RAM is critical.
Here are the specs of my PC:
120GB SSD for C: drive (that was a lot at the time) for OS and applications
500GB SSD -- second internal drive for LR catalog and image files
EVGA GeForce GT 710 video card (not expensive) running dual monitors
27" monitor - 2560x1440 (main monitor)
21" monitor - 1600x1200
You certainly don't need multiple drives or two monitors, but I would suggest an SSD as your one drive.
I haven't looked at systems like this recently, but you could check eBay, Craigslist (depending where you live), or a local shop, and I'll bet you could find something similar within your budget. (I think Dell sells refurbished PCs at good prices too.)
Hope this helps.