Up for sale is an exceedingly rare Minolta fisheye lens. If I'm not mistaken, this is a similar optical design to the 16mm Minolta Maxxum fish-eye (which costs about $1000)
Not really a whole ton to say about it, besides that it's rare and provides full-frame coverage. It provides a cool distorted perspective even on my micro four-thirds gear, but is obviously a bit impractical.
Front element has some cleaning marks (which I think showed up okay in pictures), and body shows general wear of a lens of this age, but the filters all move nicely and there is very little dust. No fungus, aperture is clean, focus is very smooth.