If you know where to look/are a little lucky, you can get an adequate RAID5 going for like $500-800 depending on the storage you need. I grabbed a QNAP 4 bay (no SSD caching) and 4x refurbished enterprise HDD's (14tb/ea) for just under $700 all-in last november if memory serves. Pretty reasonable for a 42tb RAID5 IMO.