These Photive Portable Backup Battery Chargers, originally starting at $49.99, are now $19.99 at Groupon Goods for a 2,600 mAh charger. Also available is a 5,200 mAh charger for $10 more. Both versions have free shipping and a savings of at least $5. These power banks recharge digital devices via USB port. The 2,600 mAh charges one device, while the 5,200 mAh can charge 2 devices simultaneously. These can charge cell phones, iPod, iPhone, iPad, e-book readers, digital cameras, MP3/MP4 players, and other USB devices. Sales tax is charged in most states.