$270 for a "selective focus" lens with poor correction. If you're a working pro who has no time and no assistants, need a tilting lens with poor corrections, and can expense it, maybe.
While you're at the aforementioned surplusshed.com, you can check out this book on CD: http://www.surplusshed.com/pages/item/m2797.html I have a copy. It's full of good ideas and suggestions on making simple lenses from a variety of sources, with full construction details on many mounting ideas in many formats. It's $18. For the additional $252 that a lens baby costs and a little of your time, you could make yourself a variety of similar optics.