Buying a fish eye lens adaptor?

I have a nikon d3000 and I have seen a few photos that have been taken with a fish eye lens. I can't afford a good one (about $1000) but I've heard fish eye lens adaptors are a bit of fun? I've done a bit of research and have found on ebay that you can get a 0.18x lens
(http://cgi.ebay.com/Zeikos-18x-High-Definition-Fisheye-Lens-Fish-Eye-NEW-/200515731256?pt=Camera_Lenses&hash=item2eafab3f38#ht_7514wt_1137)
Or there's ones with different focal lengths like 0.22x and 0.42x? I'm wondering what to get for the best 'fish eye lens'? Does anyone have any photos they can show me they've taken with the lenses etc?

Fisheyes are a bit gimmicky… You'll get bored with it after about 5 minutes…

you want to save your money and go for something like an ultra wide angle lens…

Save your money, and don't bother. If you want to play around with a fisheye--"to get it out of your system"--go and borrow or rent one.

As a professional photographer with over 2-decades shooting experience, I can tell you honestly that a fisheye lens is one of the most specialized lenses--and when I mean "specialized" I mean in terms of being USELESS.

Ask yourself the question: "How often am I going to be using the fisheye?" Also ask yourself "Why do I NEED this fisheye lens?" And it's very important to differentiate between "need" and "want"--especially when it comes to photo equipment.

I own/owned two of them. One was a full-fisheye and one was a full (which was stolen a long time ago) and the other is a 17mm Canon. Of the two--the 17mm was used more, and even that was infrequently.

A side note: I did not by either of them. One was given to me--and that was the full fisheye, because my best friend (who gave it to me) only used it once, and he got it as a gift from his dad. The 17mm I "inherited." I don't miss the full fisheye at all, and the 17mm gathers dust in my closet.

As a professional shooter, I keep on hand the lenses that make me money--and my bread-and-butter shots are all taken with my 16-35mm f2.8 and my 80-200mm f2.8. One thing I can almost guarantee--the market for fisheye photos is extremely limited.

Once the novelty of shooting with a fisheye wears off--which doesn't take long at all (especially with the full)--you'll find yourself with a very expensive "white elephant" on your hand.

And as far as those fisheye "adaptors"--those are an even bigger waste of money. The lens quality on those are not much better than cheap fishbowl (I couldn't resist that) glass, in many cases; and you pay far too much for what you get.

As for showing you any pictures I've taken with my fisheyes… I ditched those photos years ago (back in the days of print). I don't have them, don't want them, and don't' need them in my portfolio. And in all the years of reviewing portfolios up-and-coming photographers, I've yet to see a fisheye shot included in a serious photographer's portfolio. That's how gimmicky/novelty a fisheye lens is.

Save your money and invest in an ultra-wide or ultra-wide/rectilinear lens instead of a gimmicky fisheye.

For conclusion--you're much better off renting a fisheye and borrowing one. Go ahead and waste your money on an adapter if you want. Just know that you've been properly warned.