1000 budget is quite tight.

If just for backup and some redundancy, most will be fine with a 2 drive setup with RAID 1 Mirror. How many TBs do you need?

4 drive bay and RAID 5 is a waste if you don't need the Parity and a NAS that can have a hot spare and automatic rebuild (since you need 4 drives for that). If you need that then you need to rethink your budget.

I used to use 2 cheap DLINK RAID 1 NAS to do my daily server dump on alternate days.