As one of its daily deals, 1Sale offers the TOCCs Power Vault 10,000mAh Dual USB Power Bank, model no. PV-10000, for $17.99 with free shipping. That's the lowest total price we could find for such a power bank by $11, and also the best deal we've seen for any 10,000mAh backup battery. Deal ends today.
Expect this item to take one to two weeks to arrive.