Taking surveys online is a great way to earn a little "spending money" on the side. You won't get rich by any means, but it can provide some nice bonus money. I typically use my survey earnings for Amazon gift cards, because we shop on Amazon a lot (and I mean, A LOT!).
Here is a list of companies that I can recommend - I currently take surveys with all of these companies and can personally vouch for them! Just click on the image to sign up with that particular survey company.
And finally, anyone can apply to join Opinion Outpost.