The first thing I use is swagbucks. Swagbucks is a search engine that you can use to earn "swagbucks." When you randomly search for things you will earn these swagbucks. Then you can trade in your swagbucks for gift cards and other prizes. I always cash in my swagbucks for amazon gift cards. I've probably earned $100 in amazon gift cards so far. I highly recommend using this site. Even if you don't like the search engine if you just make a random search you are likely to earn swagbucks and then you can go use the search engine you prefer. If you think you'd like try it click the banner below and I will get a refferal. Referall's also lead to free prizes so then make sure to tell your friends about it.
The second thing I use is Ebates. Ebates is a site that you can go through to get cash back for online purchases. All you have to do is log on to ebates and search for wherever you want to shop at online. Then from their make your purchase. It even will tell you online coupon codes you can use to save you even more money. I earned $22 just for purchases my textbooks online.
Another great site I use to find coupon codes is retailmenot.com. Here you can search for coupons to use online or to print out for stores. If you take the time to search for a discount then you will most likely find that their is a discount out there somewhere. I rarely pay full price for anything anymore and you don't have to either.