AllPowersDirect via Amazon offers its AllPowers 15,000mAh Dual USB Solar Portable Battery Pack in Orange for $23.99. Coupon code "RFMA6G8D" cuts that to $16.79. Plus, Prime members bag free shipping. That's the lowest price we could find by around $13. It features 2.1-amp and 2.4-amp ports. Deal ends December 19.

Update: The price has increased to $24.99 before coupon, $17.49 after.