Adorama offers the Digital King Magnet Mount Conversion Fish Eye Lens for iPhone 4 and 5, model no. 000DK180, for $29.99 with free shipping. That's the lowest total price we could find by $12. It features 0.2x magnification, 180-degree view angle, and carry pouch.

Also available is the Digital King Magnet Mount Conversion Wide Angle & Macro Lens for iPhone 4 and 5, model no. 000DKWIDE, for $29.99 with free shipping. That's the lowest total price we could find by $10. It features 0.5x magnification and up to 100-degree view angle.