Using discount code I8TPBEG6, you can save £1 on this Vinsic Classic 5,000mAh power bank, bringing it down from £10.99 to £9.99.
Comes with a free micro USB cable. Compatible with iPhone, iPod and iPad, too, but you’ll need to supply your own cable (which presumably you'll have, if you - like - ever charge your device).
Sold by High Tech International and Fulfilled by Amazon, so Amazon takes care of the picking, packing, shipping and customer service.
(Thanks to FreezingKitty at HUKD)