@gaming-trail So I will list the prices for my country (which usually are bigger than in the rest of the world) from the day I've bought them, with the conversion rate RON to USD from this date (25-June-2017). And I don't mind if you include it in the "best of gaming" of today, I will actually thank you!

So, we have:

The GPU : approximately $340
The monitor: LG 24MP68, with free sync, 23.8", approximately $170
The adapter: $35 at the time of purchase, now it's $38 ( you can probably get it cheaper with coupons or by ordering it from the app of AliExpress )

link adapter : https://www.aliexpress.com/item/EXP-GDC-Laptop-External-Independent-Video-Card-Dock-with-PCI-E-Interface-Black/32456172794.html?spm=2114.13010608.0.0.qXNuZg

PSU: approximately $50 ( second hand).

Total cost: $600

I don't recommend doing this kind of investing right now because of the huge prices of GPUs, but it's a good investment when everything goes back to normal... Also, I can't stress that enough: buy AMD GPU with A LOT OF MEMORY, the 8GB variant is worth it! You can go for the 4GB but the hiccups will appear in a lot more open world titles.

I hope it helps!