The Energizer XP3000A Portable Charger is retailing for S$59.90. It has a capacity of 3,000 mAh which is able to charge your iPhone 5 about two times before needing a recharge and it weighs 130g.
What makes the XP3000A special is the built-in lightning cable. This means you do not need to bring along another cable if you are using it with your iPhone 5.