If you're on a really tight budget and live in a big enough city, go with used parts if you can. Just be careful about GPU crypto miners. It they're selling a bunch of used GPUs, they're probably a miner. Do not buy a pre-built system, 95% of them are all garbage. Building your own system is and always will be far cheaper than buying a prebuilt anyway.
Also, I recommend against laptops as they almost always struggle with heat and therefore have issues with gaming (not to mention heavily overpriced for what little performance they offer).
If you can manage: Ryzen 2500x, or 2600, or 2600x, etc (or Intel equivalent) or better (avoid AMD APUs (xxxxG series) as they lack gaming performance), B450 motherboard (or Intel supported board), 8 - 16GB of ram (16GB recommended for stability), any ssd, and either a GTX 1060, or GTX 1660, or RTX 2060, or RTX 3060, etc (or AMD equivalent or better). Make sure the computer case has proper airflow, never get sucked into that clear glass front and side panel nonsense as most of those all have terrible airflow. A system like this should be able to get you medium graphics settings or better at 45+fps. The only reason I don't recommend a Ryzen 1600x or a B350 motherboard is because it's first gen which is a pain in the butt with ram support.