This should be able to suit your needs. I put an ssd but if you want a hard drive just take it out a throw a seagate barracuda in there. This should run any game. CSGO would be no problem.
PCPartPicker part list:
http://pcpartpicker.com/p/fr8Fpg
Price breakdown by merchant: http://pcpartpicker.com/p/fr8Fpg/by_merchant/
CPU: Intel Pentium G3258 3.2GHz Dual-Core Processor ($68.98 @ OutletPC)
Motherboard: MSI H81M-P33 Micro ATX LGA1150 Motherboard ($44.99 @ Directron)
Memory: Kingston Fury Series 8GB (2 x 4GB) DDR3-1600 Memory ($66.99 @ Newegg)
Storage: Samsung 840 EVO 120GB 2.5" Solid State Drive ($71.97 @ OutletPC)
Video Card: Asus GeForce GTX 750 Ti 2GB Video Card ($128.98 @ OutletPC)
Case: NZXT Source 210 (Black) ATX Mid Tower Case ($29.98 @ OutletPC)
Power Supply: SeaSonic 620W 80+ Bronze Certified Fully-Modular ATX Power Supply ($54.99 @ Amazon)
Total: $466.88
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-01-09 18:25 EST-0500