Good, affordable fisheye lens, adapter or filter?

Does anybody know of any decent, affordable (as in under $150 or so) fisheye lenses, adapters or filters for Nikon? Not looking for anything superb, but just to take some mess around pictures/videos with not too much blur or fuzz. Any suggestions would be great and will pick best answer.

Good = interchangeable fisheye lens / $300 to $1, 200
Adapter/Filter = JUNK /$40.

http://www.amazon.com/...B002KMAWO0

http://www.amazon.com/...B000144I30

http://www.amazon.com/...B000GE9SBM

Avoid the junk. So called adapters can't cover the full 180 degrees that defines a fisheye lens, NOT the distortion they cause

Sure, They are not great, but not too bad either. I got this one for under $40 on E-BAY. See if it's good enough for you.https://picasaweb.google.com/113469061768012111877/AroundTheHouse#5719562406117329858

That is a shot of my living room and it's almost 180 degrees.