Motherboard with CPU 400 or so.
Memory ddr3 3G 100 or so.
The hard disk is about 320G 250.
Mouse and keyboard case 100
Chassis power supply 300
The size of the display is about 700.
400-600 with graphics card gt240 or so.
Can be controlled within 3000
It depends on you personally.
With this configuration, it is no problem to open 3 to 4.