300 USD budget build for a buddy

[Dr. Max Del]

so a friend has chosen to build a computer for 300 or so bucks. gonna give em my spare gpu and cpu so that saves some cash there

Budget: ~$300
Resolution: gonna be using an old 1080 x1024 monitor but 720p would nice to aim for

Games / Settings Desired: medium settings, no clue on games he wants to play
Any other intensive software or special things you do: none
Country: USA

Parts that can be reused: from an old of mine i have a i3 2120 http://www.newegg.com/Product/Produc...82E16819115077
and sapphire radeon 6850 http://www.newegg.com/Product/Produc...82E16814102908

Do you need an OS: yes(may be able to get by with ubuntu or mint though)
Do you need peripherals (e.g. monitor, mouse, keyboard, speakers, etc): need mouse, keyboard, and speakers

[Deleted]

Windows is ~$90 so that's not going to happen unless he/she can get it for free (student, work or w/e)

PCPartPicker part list / Price breakdown by merchant

Motherboard: MSI H61M-E33/W8 Micro ATX LGA1155 Motherboard ($26.99 @ Newegg)
Memory: G.Skill Sniper 8GB (2 x 4GB) DDR3-1600 Memory ($57.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($53.89 @ Directron)
Case: NZXT Source 210 (Black) ATX Mid Tower Case ($34.99 @ Micro Center)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($28.99 @ NCIX US)
Keyboard: Logitech K120 Wired Standard Keyboard ($19.98 @ Newegg)
Speakers: Logitech Z313 25W 2.1ch Speakers ($39.99 @ Best Buy)
Other: Anker® Full-Size Ergonomic Wireless Mouse ($13.00)
Total: $275.82
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-11-22 13:54 EST-0500

The mouse is wireless but has good battery life and excellent feedback/reviews for such a cheap mouse. There is a custom link to it when you check the parts list.