You have to shop around. one place will be alot cheaper on one item and much more expensive on another.

 

You could start at the Algorithm shop on the HWY north of the Cangs Store towards Sibulan, same side of the street.

 

As suggested already you want to go to Algorithm. That is where I have gone for years and I'm a gamer as well. As a further note you'd find the cheapest and best options is custom built (which they can do for you) and pretty much all the other places lack much of what is needed to build a proper computer.