In your budget, I would recommend
Processor: AMD Fx-6300/4300 (around $110)
Motherboard: Gigabyte GA-970A-UD3P (around $80)
Graphics Card: AMD 7790/Radeon R7 260X (around $110)
RAM: G.SKILL Ripjaws Series 8GB (2 x 4GB) (around $35)
PSU: Logisys 550 Watt (around $18)
HDD: opt for 1TB hard drive with 7200rpm (around $60)
Cabinet: Rosewill Micro ATX Mini (around $30)
Thanks