ebay (via bestpriceoptics) has the Rokinon 8mm f/3.5 fisheye lens for $189.99 (reg. $229) in limited quantity. The lens is available for Canon, Nikon Sony A, Sony E, Pentax and Olympus mounts. Check it out here on ebay.
B&H has the Bower 8mm f/3.5 Fisheye lens for $209. It is available in Canon, Nikon, Sony A-mount, Sony E-mount, Pentax, Olympus and Samsung NX mount options. Nikon and Olympus 4/3 focus confirm chipped version run $229 and $239. Check them all out here at B&H Photo.