Newegg offers the RAVPower Element 10,400mAh External Battery Pack in White, model no. RP-PB07, for $34.99. Coupon code "EMCYTZT58997" cuts it to $25.99. With free shipping, that's the lowest total price we could find by $4, although last month we saw it in a different color for a buck less. It features 1-amp and 2.1-amp USB outputs and is compatible with iPhone, iPad, iPod, and most smartphones.