I am assuming that you do not need a monitor, keyboard and mouse or speakers with your budget.
Have a look at these.
Chillblast Fusion Hurricane. A little more than your budget but a nice PC with a decent graphics card, in fact overall a decent spec.
Chillblast Fusion Boost. Do not be put off by the size of this,again it is an excellent build, I have the same case for one of my builds, and well worth considering.
Chillblast Fusion Elixir. Again a decent gaming PC.