What are some good Fish eye lens to buy for a Nikon D3100?

I want a good Fish eye lens, but i don't have tons of money, but what's a good fisheye lens in a good price range?

What is a good price range to you?

The Bower/Samyang 8mm f/3.5 is the cheapest one that i'd consider:
http://www.adorama.com/...mm+fisheye

Be careful, it's available for several different brands of cameras but these versions are not interchangeable.

You should definitely look out for a walimex/samyang (basically the same lens, only the names are different) 8mm f/3.5 fisheye. It is a really decent lens, especially when stopped down to about f/8 and it is also quite cheap. It's only disatvantage is, that it's fully manual, meaning you have to focus and set the aperture ring manually. But this is not a real problem, because you don't actually need to focus very precisely when shooting with a fisheye, since the dof is huge. Just one more thing: don't ever forget to stop it down as it is really awful wide open. Fisheye lenses weren't meant to be shot wide open anyway.

Have a look at Precision Design 0.25x Super AF Fisheye Lens

All glass lens elements; Exceptionally large depth of field
Reduces your lenses focal length by an amazing.25X; Offers attention-grabbing and distinctive perspectives
Optimized to work with almost any lens with a minimum focal length from 18mm to 50mm
Includes set of adapter rings to work with 52mm, 55mm, 58mm & 62mm filter diameters
Can offer ultra wide angle, diagonal fisheye and circular fisheye images; Especially useful for real estate or shooting in confined spaces