As one of its daily deals, Staples offers the PowerNow! 10,000mAh Power Bank Portable Charger in
Blue, model no. 9093PG; Purple, model no. 9092PG; or Red, model no. 9094PG; for $14.99. Plus, Staples Rewards members receive free shipping. (Not a member? It's free to join.) That's $45 off list and the lowest total price we could find. It can simultaneously charge a tablet and Smartphone and purports to provide enough power to recharge typical Smartphones four to five times.