BestDealUSA via Amazon offers the 1900mAh Backup Battery for iPhone / iPod in Black for $6.32. With 50 cents for shipping, that's $3 under our mention from last fall and the lowest total price we could find for such a device by a buck. This charging stand is compatible with the Apple iPhone 4, 3G, and 3GS. It's purported to offer a 4-hour mobile charge.