Sunvalleytek via Amazon offers the RAVPower Dynamo-On-the-Go 7,800mAh External Battery Pack, model no. RP-PB09, for $33.99. Coupon code "5PLFWTKU" cuts it to $24.99. That's the lowest total price we could find by $11. (We saw it bundled with a car charger for $2 more in March.) It features a power level indicator, dual micro USB ports, a wall charger, and carrying bag.