As one of its daily deals, Best Buy via eBay offers the ChargeIt 13,000mAh Power Flask Portable Charger in Black, model no. 8650, for $29.99 with free shipping. That's the lowest total price we could find by $9. It charges up to three devices at once, and features an LED indicator.

Of note, it's also available in Brown, model no. 09089-PG, for $29.99 plus $3.99 for shipping. Both deals end today.