HandHeldItems offers the Odoyo Ultra Slim Case for iPhone 4 / 4S in eight colors (Green pictured) for $12.99. Coupon code "odoyoslimiphone4s" cuts it to $5.99. With $2.85 for shipping, that's the lowest total price we could find by $9. This case touts a 1mm thickness, matte finish, and access to all ports and buttons. Coupon expires September 30.