As one of its daily deals, Best Buy offers the MyCharge All Terrain 3,000mAh Portable Power Bank in Gray/Orange, model no. AT30G, for $19.99 with free shipping. That's the lowest price we could find by $9. It features a built-in 2.1-amp USB port, up to a purported 22 hours of extra power, and wrist strap. Deal ends today.