LivingSocial has the LiveItNexus 3-in-1 iPhone-Compatible Smartphone Camera Lens Kit for only $25.  According to LivingSocial this kit retails for $125, although there are other comparable sets for a bit cheaper.  This kit includes a fisheye lens, wide-angle lens, and macro lens. (You can find the deal about halfway down the page)

Thanks to your smartphone camera, you can snap a shot of anything, bright or dark, even the color of your coloured contacts, any time–but not everything fits into the frame when you simply point and shoot. Make sure your subjects are always fully in view with this deal from LiveItNexus