Is it Vitacon? Or something with 'King'? Anyway, crap. A fish-eye lens is different from a normal lens (hint: distortions), no adapter can mimic a good fish-eye lens. Regarding those adapters you can read more here: http://www.clubsnap.com/forums/showthread.php?t=477934
Define "bomb" for you, vulgo: budget.
You can get a manual FE lens like Zenit 16mm f/2.8 for less than $400. But that's a full frame lens and the fish-eye effect will be limited on a crop-sensor camera. AFAIK, the Tokina fish-eye is made for crop-sensor (if I'm wrong please correct me). Further details in the Price Guide section.