SSDs are about $400/TB for raw storage. Prices are substantially different for consumer and enterprise spaces, but 4TB disks (Micron, Samsung, etc) tend to be about $1500 and 8TB around $3200. If you factor in redundancy, you're looking at around $1000-1500 per TB of usable storage.

This also isn't a matter of "just go with cheaper consumer disks". If you care at all about data integrity you won't use consumer-grade SSDs.