Which Fisheye Lens for a Nikon D60?

I have a Nikon DSLR D60 and really want to experiment more with different shots. I have been looking around Amazon for ages and various other shops for a decent Lens or an attachment that screws on to the basic lens, however because of price i can't afford a professional one that costs at least £300 + so was looking for something similar to an Opteka model or something for £50 and under.

I just need help deciding which to buy as i find i can never trust online reviews and descriptions, someone help me please: D

The 'screw on' fisheye lens are very cheap in terms of quality and performance.

These lens give an effect of more 'barrel distortion' instead of a real, true fisheye lens which gives an extremely wide angle of view.