When it comes to making financial decisions, from switching energy providers to buying car insurance, millions of us rely on price comparison sites to find the right deal. But how reliable are they? The Money Programme's Rachel Horne investigates the sites and examines the methods they employ. The price comparison site industry didn't exist a decade ago and it is now worth hundreds of millions of pounds. But with so much money to be made, how do we know the information they provide is totally impartial? Rachel Horne highlights some of the tricks of the trade used by companies to help ensure they are featured on that all-important first page, and investigates how some sites pass on our personal information to others. There's little doubt price comparison sites can help us navigate through confusing financial decisions - but with so much money resting on them, are they adequately regulated?