sidtech

I am planning to build a NAS system for my personal use. I don't know anything about server hardware and I need some help from where to start and what will be the cost involved and all the power requirements and, is it worth buying a used dell server and using it as a personal home server. Oh and if the whole thing excluding hard drives cost under 200$(US) it'll be great. Edit: I also want to stream media using the PLEX platform.