Hi, there are a load of survey sites out there. Likewise mystery shopping can be a good bet. I appreciate you have to leave the house to do this, but if you can combine it with your regular shops, then it need be little inconvenience and could be a great way to get a little money for the unexpected costs!
I may get told off for doing this, but in fairness I can't see a forum about this on money supermarket, so I'm hoping they'll forgive me!!
Money saving expert forums (sorry!!!) have an extensive section on surveys and mystery shopping, including views on which companies pay out etc. They may be your best bet.
Moneysupermarket people - sorry - this doesn't seem to be covered on your site so I really hope you don't mind me pointing alishasmum to the best source of information I knew.