If you don't have the money to buy a decent PC, dont't buy it at all. Rather buy a notebook. Portable, has a built in screen, keyboard, and mouse (Touchpad xD). It will be a lot better for you. Todays notebook standards is more than the pc that you want to build right now. Or just dont build a PC, buy it from some kind of manufacturer like HP. It will be cheaper. Building PC's is cheaper when you want a higher-end PC. Because Higher-end PC's are overpriced unless you build them (most of the time).
I already have a notebook, and I will do as I please with my money