RecycleBank is a website you should definitely be a part of! The main point of the site is to raise people's awareness about being "green".
Once you sign up (and get 25 points instantly!) you can start earning more points with codes (a quick google search will reveal 100+ points worth of codes) or by taking part in the activities under the "earn" tab on their page.
You could earn enough points to get gift cards, but there are better sites for that and the coupons here are so good that they are the real highlight.
-2 Free cans of Fancy Feast Elegant Medleys cat food for just 75 points!
-Buy 1 Get 1 Free 2 Liter Coke products just 60 points!
-$1 off ANY Coke product for 50 points!
-$10 off a $50 Purchase (before coupons) at Food 4 Less, Save Mart, Lucky or Nugget for 100 points!
-1 Free bag (10 oz or larger) of Wonderful Pistachios for 200 points!
-$2 off Wonderful Pistachios only 50 points!
There are many more coupons too! Check them out here
The sign up is completely free and I get hardly any emails from them!