Newegg offers the Luxa2 P10 10,000mAh Dual USB Battery Pack, model no. PO-UNP-PCP0BK-00, for $29.99. This $10 mail-in rebate cuts that to $19.99. With free shipping, that's the lowest total price we could find by $15. It features one 2.1A port, one 1A port, and an OLED battery status indicator. Deal ends October 23.