Directron offers the Sans Digital TowerRAID 4-Bay Serial SAS / SATA RAID 5 Storage Enclosure, model no. TR4X+BHA, for $329.99. Coupon code “reseller2discount” cuts it to $323.39. With $10.20 for shipping, that’s $37 off list and the lowest total price we could find, outside of the price below. It supports four 3.5″ SAS or SATA hard disk drives and features a PCI-Express 4x controller, over 300MB/s read write performance, and more.

A close price: mwave has it for $339.99 with free shipping.