Firemall LLC via Amazon offers Prime members the Veho Pebble 6,600mAh Battery Folio Case and Stand in Tan, model no. VPP-003-TAN, for $19.99 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, it adds $8.41.) That's the lowest total price we could find by $10. Designed for use with the iPad, iPad 2, and iPad Retina, it's also compatible with most mobile devices and features a magnetic closure and zippered pockets for connectors.