Well, 1300-300=$1000.....
But I can do a $700 as well.
Here's $700.
PCPartPicker part list:
http://pcpartpicker.com/p/j3RF
Price breakdown by merchant: http://pcpartpicker.com/p/j3RF/by_merchant/
Benchmarks: http://pcpartpicker.com/p/j3RF/benchmarks/
CPU: Intel Core i5-3450 3.1GHz Quad-Core Processor ($179.99 @ Amazon)
Motherboard: ASRock H77M Micro ATX LGA1155 Motherboard ($69.99 @ Newegg)
Memory: Corsair XMS3 8GB (2 x 4GB) DDR3-1333 Memory ($38.99 @ Newegg)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($58.88 @ NCIX US)
Video Card: Asus Radeon HD 7870 2GB Video Card ($237.86 @ Newegg)
Case: Antec Three Hundred ATX Mid Tower Case ($39.98 @ NCIX US)
Power Supply: Antec Neo Eco 520W 80 PLUS Certified ATX12V / EPS12V Power Supply ($46.98 @ Newegg)
Total: $672.67
(Prices include shipping, taxes, and discounts when available.)
Here's a $1300:
PCPartPicker part list:
http://pcpartpicker.com/p/j3UV
Price breakdown by merchant: http://pcpartpicker.com/p/j3UV/by_merchant/
Benchmarks: http://pcpartpicker.com/p/j3UV/benchmarks/
CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($189.99 @ Microcenter)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($27.98 @ NCIX US)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($134.99 @ Amazon)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($41.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($77.99 @ SuperBiiz)
Storage: Samsung 830 Series 128GB 2.5" Solid State Disk ($102.98 @ NCIX US)
Video Card: Sapphire Radeon HD 7970 3GB Video Card ($387.86 @ Newegg)
Case: Antec Three Hundred Illusion ATX Mid Tower Case ($69.99 @ Newegg)
Power Supply: Corsair Enthusiast 650W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($69.99 @ Newegg)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($14.99 @ Newegg)
Total: $1118.75
(Prices include shipping, taxes, and discounts when available.)
That leaves you enough for a monitor, mouse, keyboard and whatever else you want.