Swagbucks is another site you NEED to join. It's one of my favourites and there's free money up for grabs every single day. You can be part of a community of 15+ million members who have already earned over £84 million.
Basically you take surveys and complete tasks and they reward you with their reward currency called SBs. You can then exchange those SBs for gift vouchers from the likes of TK Maxx, M&S and Amazon
Make sure you confirm your e-mail address with them when you join because that gives you immediate access to a couple of Gold Surveys which give much higher rewards.