Newegg offers the RAVPower 10,400mAh External Battery Pack in Black (pictured), model no. RP-PB07, bundled with the Scosche Dual USB Home Charger, model no. GPSPWRR, for $23.99 with free shipping. (The charger will add automatically to cart.) That's $9 under the lowest total price we could find for these items purchased separately elsewhere. (For further comparison, we saw the battery pack alone for $24 with free shipping three weeks ago.) The battery pack features 1-amp and 2.1-amp USB outputs and is compatible with iPhone, iPad, iPod, and many smartphones. The charger includes two adapters.
Update: Linked text corrected.