Amazon: OtterBox Defender Case for iPhone 3G/3GS $12.99 December 7, 2010 This post may contain a link to an affiliate. See my disclosure policy for more information. If you missed this deal on Cyber Monday, it’s back! Currently, Amazon is offering up the OtterBox Defender Case for iPhone 3G, 3GS (Black) for only $12.99! This ships FREE with your Amazon Prime membership or on an order of $25 or more.