Amazon offers its Amazon Prime members the Be a HeadCase Bottle Opener Phone Case for iPhone 3G & 3GS, model no. DM01, for $13.18 with free shipping. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $5.05.) That's the lowest total price we could find by $2. This plastic case features a stainless steel bottle opener and can tab opener and comes with a free app that counts the tops and cans popped.

Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months.