PCPartPicker.com is a very good site for both new and experienced computer builders. It helps out with compatibility, cheapest vendors and lets you post a link to your planned build.
Here is my hubby's computer that he got at Christmas --> http://pcpartpicker.com/p/sZBsP6
PC includes not only central processor.
Also:
Motherboard ~120-300$
Memory modules ~100$
Video Card - ~250-400$
PSU(Power Supply Unit) - ~150$
HDD/SSD. - ~100-300$
Good gaming processors now starts at Intel Core I5 ~250$
Intel pentium g3258 anniversary edition is a crap among crap.
It's good for office applications, like MS Word/Excel, but not for gaming.