Planning to build a NAS for home storage

[Spaztoid1]

Help, I 'm planning to build a home NAS for storing files and such but I really have no idea where I'm going with this so I would need some help.

 

Some of the requirements would be that it is around $600 USD in budget and has at least 4tb of storage with room to grow. Other than that I really have nothing else to say other than a small form factor would be favorable but not a requirement.

 

Thanks!

[Killervolt]

Maybe this?

PCPartPicker part list / Price breakdown by merchant

CPU: AMD A8-7600 3.1GHz Quad-Core Processor  ($77.99 @ SuperBiiz) 
Motherboard: ASRock FM2A68M-DG3+ Micro ATX FM2+ Motherboard  ($44.99 @ SuperBiiz) 
Memory: G.Skill NS 4GB (2 x 2GB) DDR3-1333 Memory  ($23.99 @ Newegg) 
Storage: Sandisk SSD PLUS 120GB 2.5" Solid State Drive  ($43.94 @ Amazon) 
Storage: Western Digital Red 4TB 3.5" 5900RPM Internal Hard Drive  ($149.89 @ OutletPC) 
Case: Corsair Air 240 MicroATX Mid Tower Case  ($64.99 @ Micro Center) 
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX Power Supply  ($55.99 @ SuperBiiz) 
Total: $461.78
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-02-08 21:59 EST-0500

If you want, with the extra budget you can get another WD Red for RAID.