TigerDirect offers the Snow Lizard Power Tek Portable 7000mAh Tablet and Cell Charger
in White, model no. SNPWRDC7, for $35.97
for shipping. That's $21 under our January mention (which required a rebate) and the lowest total price we could find by $2. It can charge your tablet or cellphone for up to 9 hours and features two USB ports for simultaneous charging.