power supply Corsair VS450 1750
graphics card Palit GTX 1050 StormX 2gb 5750
processor Intel Pentium G4400 3.30 GHz Kabylake 2450
Motherboard lga1151 ASRock H110M-DVS 3250
HDD Western Digital WD Caviar Blue 1TB 64MB 2350
RAM Corsair Vengeance LPX 4GB 1x4gb 2400Mhz 2250
Monitor : Just buy something you like with the remaining funds (most likely you can buy a 17" or 18.5" monitor with the remaining funds)
Casing : Just buy something you like with the remaining funds (I'm not really picky with casing so I don't have that much knowledge about it)
I had to cheap out on some of the parts coz honestly 20k for a brand new rig with the monitor included is a bit short. I didn't cheap out on the important ones though. I based this price on brand new prices on TPC so the prices above may not be the exact price.