If you are readying yourself for Glastonbury, Download or Reading and Leeds for the summer weather, a power bank can be a worthy investment. While you're taking all those selfies and pictures, battery life can drain fast - but what if we told you that you could get a Belkin power bank for just five Great British Pounds? Sounds almost too good to be true, doesn't it? Well, thanks to TopCashback and Argos, you can do just that. The Belkin 10000mAh power bank is currently £19.99 on sale at Argos.