If you're a college student you might be able to get Windows free through DreamSpark. Also check if you have a Micro Center or Fry's nearby, they usually have good deals on computer parts.
Very solid build above Razer, only thing I would suggest swapping out is the motherboard, go for the Gigabyte Z170 HD3, it's a great deal atm at $82 and is one of the best value Z170 boards around.