12,000 CPU: I5 Haswell 4430 - 4460 from intel
05,500 Mobo: B85 LGA 1150 from Gigabyte/Asrock/MSI
05,500 RAM: 1600 MHz C9 4 GB X 2 = 8 GB from Corsair/GSkill
10,000 GPU: Nvidia GTX 750 TI from Gigabyte/Asus/Zotac
03,000 HDD: 7200 rpm 3.5" 1 TB from Seagate
01,000 ODD: LG DVD R/W
03,500 Case: Mid-tower cabinet from Corsair/Cooler master
02,500 PSU: 80plus bronze 430 - 550 w from corsair/Antec/Cooler Master
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43,000 half life's contemporary gaming build
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Notes
- prices are approximate
- I recommend shopping in stores rather than online due to genuineness, warranty returns etc
- I am not sure if you already have speakers to go with your build, if not, buy something around 1500 from Logitech/creative