This iTD Gear 5000mAh Solar Power Bank with Dual USB Ports drops from $39.99 to $14.99 to $11.99 using our exclusive coupon code BRDSOLAR at iTechDeals.com. Plus, the shipping is free. This is the lowest price we could find for any similar solar power bank by $3. It has a carabiner attachment and is water and dust-proof so you can attach it to a backpack and let it charge as you go about your day. It also has dual USB ports so it can charge two devices simultaneously. There is no sales tax.