PCPartPicker part list:
http://pcpartpicker.com/p/9Ryjt6
Price breakdown by merchant: http://pcpartpicker.com/p/9Ryjt6/by_merchant/
CPU: Intel Core i3-6100 3.7GHz Dual-Core Processor ($124.48 @ Amazon)
Motherboard: Asus B150M-A D3 Micro ATX LGA1151 Motherboard ($72.99 @ Amazon)
Memory: Mushkin ECO2 8GB (2 x 4GB) DDR3-1600 Memory ($29.99 @ Newegg)
Storage: Toshiba P300 1TB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Amazon)
Video Card: PowerColor Radeon R7 370 2GB PCS+ Video Card ($128.99 @ NCIX US)
Case: Deepcool TESSERACT WH ATX Mid Tower Case ($40.98 @ Newegg)
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX Power Supply ($55.99 @ SuperBiiz)
Total: $503.41
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-02-07 12:23 EST-0500
You dont need the Z170 chipset, you can get a B150 and get the same performance considering that the i3 can't overclock anyway. I really think this is the way to go personally with this build. You might consider looking at some used parts as you can find some really good stuff but this will get you playing games resonable well.