Telesport via Amazon offers the Paxcess 100-watt 40,800mAh Portable Generator Power Inverter / Battery Pack for $143.88. (Select the regular price option, not the lightning deal.) Coupon code "4ILMYYOT" drops it to $99.28. With free shipping, that's $201 off the lowest price we could find. It can be charged by a solar panel (not included), wall outlet, or vehicle (12-volt adapter included) and features AC, DC, and USB power outputs.