Reddit mentions of HighPoint RocketRAID 2782 PCI-e X16 SAS/SATA 6Gb/s RAID Controller

Sure, although my system is COMPLETE OVERKILL, so you dont need anything nearly as serious. I wouldnt be surprised if I get plenty of people criticizing my build specs because most of it is unused/unneeded. you could use a basic CPU which could be found for probably as low as about $50 and get by if all youre doing is hosting files (still supporting ECC), and most anyone doesnt need 4xgigabit lan, or support for 512GB ram, or dual CPUs like im running. You could do it for way cheaper than I did, so dont let my build scare you away. I would recommend server grade components, but even entry level (or close to it) server grade would probably get you by. I got some parts for next to nothing which helped bush me to a complete overkill build as apposed to a more practical at a little less $$. browse through the freenas forums and /r/freenas to get better ideas, or even post asking for build suggestions.

anyways, heres the specs of my build:

CPU: 2x intel xeon e5-2620v2 (I got these for $100 each from a friend, only reason I went with them.. complete overkill)

motherboard: ASRock EP2C602-4L/D16 SSI EEB Server Motherboard Dual LGA 2011 Intel C602 DDR3 1600/1333/1066

Memory: 2x Kingston 32GB (4 x 8GB) 240-Pin DDR3 SDRAM ECC Registered DDR3 1600

Case: Norco RPC-4224

SATA/SAS controller highpoint rocketraid 2782 32 port I went with this card because amazon had some sort of a pricing error, and I grabbed it at ~$180. Reviews arent great that ive seen, but its been solid for me.
My power supply is one I had laying around, I cant remember the model, but I believe its about 750 watts (maybe 850.. cant remember.. its more than enough either way)

and Im currently running FreeNAS on a usb stick, with 12x Western Digital WD40EFRX 4TB Red drives, and 2 500GB 2.5" drives I had laying around (WD - cant remember which model) which are running the Jails (programs/addons) mounted inside the case

I run plex media server /r/plex and have several people running transcoded streams at once, so I wanted plenty of CPU, but Ive never used as much as 50% of my computing power when ive had as many as 7 people streaming transcoded streams at one time. Other than that, most other service I run on it are rather low demand. if you wanted to run something like plex (or anything that is CPU hungry) building is a huge benefit since any prebuilt system will have which CPU they chose, and its usually not intended for much more than shooting files to a few different systems (some do have better CPUs though, at a cost of course)

also, another option is NAS4Free (which was forked off of FreeNAS when freenas developed into more feature filled and not just a NAS OS). Ive never used NAS4Free as it was more limited than I wanted to get into, but its supposed to be more user friendly if youre looking more for a basic NAS and not trying to use it for much more server purposes, or at least thats my understanding, I never dove into it much so I could be mistaking.