I snagged a couple BNIB promise supertrak ex16350s. I paid 125 each (which was too much, he was letting them go for 100 later).
That's a 16 port hardware raid card (raid 6 too) and it came with 2 port splitters (so 4 drives each) and power adapters.
It's going to make a nice 12 TB server
Forget raid 5. Go 6 or 10. You want to be able to sustain multiple drive failures. Drives are too big and unreliable nowadays. One of those pos could end up erroring before it finishes rebuilding 2-3 TB, then you're up shit creek.