Need help building a budget PC

[optimistictwat]

If it's relevant; I don't live in North America and I'll probably buy most of the parts from Amazon.
Been wanting to get a PC for a while but thanks to a series of unfortunate events I had to reconsider building a PC with the parts I wanted. Now, I still want to get a gaming PC but now I have to deal with a deflated budget. I was looking for something that can perform at least at the same level as a 'current' gen console (normie XBOX One and PS4) and although I do want to cut expenses where possible, I also don't want to save some 20 bucks in something that's going to be a lot inferior and less reliable than a slightly more expensive counterpart.
I was thinking of getting an AMD GPU, maybe an RX 580.
I also wanted to ask; would you guys recommend buying a used GPU online? I've seen some for a good price (not that much cheaper than a new one but still an attractive price) and I was wondering if buying it used is a good idea.
Also, can you guys recommend me monitor? I already got one, although is a bit old and i was thinking about getting a new one but I really have no idea which one to buy.

 

[kindangrysliceofpie]

It depends. some offers are sketchy, but it really depends. Do you need a monitor, mouse, and keyboard or not? You can build a PC for $500 that would outperform any console.

 

[optimistictwat]

Yes, but I intend to replace them as soon as I can. They're working fine, though, so I'll probably only buy them a few months after I have bought the priority stuff.