FREE money! I'm usually so dubious about this kind of think and people keep asking if it's a scam! It isn't too good to be true it's such an easy way of earning free money as well as potentially saving some with better deals on insurances etc...
If you shop online like me, you just use this site first and are then re-directed as normal and it tracks your visit! Seriously - get on it. I've just paid £95 into my bank to pay off a credit card so even more savings on the interest there!