Whether you're buying a house or a hairdryer, the chances are you'll have looked at an online review site to work out what you're likely to get for your money. The government's Competition and Markets Authority estimates that every year £23 billion of UK consumer spending is influenced by online reviews. But can they all be trusted? 5 live Investigates reveals how easy it is to buy fake five star reviews on one of the world's biggest online platforms and how people are still being paid to leave fake reviews for products sold on Amazon - despite a crackdown by the company more than a year ago.