Hot Coupon World has a list of 19 legit survey sites that PAY you with the added bonus of little to no spam. What a GREAT way to earn some extra money with little effort. As a participant myself, I do suggest creating a dedicated email address for joining such sites, just in case they do send the occasional email newsletter or reminder.
Click here to see the complete list that Hot Coupon World has created. Of those listed, I think MyPoints is my favorite, simply because you don't have to do a darn thing to earn points, other than click through the email(s) they send. Once you have accumulated enough points, simply "cash" them in for gift cards good at your favorite store(s)!