GO HERE and sign up for swagbucks if you haven't already! log in EVERYDAY and more than once a day on FRIDAY for MEGA BUCKS! you will earn random BUCKS for doing things like searching (instead of google searches) watching video clips and even cashing in coupons! I cash in for the $5 amazon gc because they give me more "bang for my buck" you can do this up to 5x per reward per month. once you get your code go on over to AMAZON and log in to your account, once you do you can add your gift certificates in and watch them add up (bank them) until you find something you really need or want or save them for Christmas!
I also collect Amazon GC from my Credit Cards and some of my contest wins and blog rewards pay in kind as well. Last year I had many of them and was able to buy a nice KINDLE for my daughter for Christmas along with some other things. This year I have spent them as quickly as I could earn them on necessity items like vitamins, bday gifts etc instead of charging them.
How ever you decide to do it, it doesn't matter, what matters is THAT YOU DO IT! where else can you earn FREE AMAZON GC AS EASILY? if you can FILL ME IN, because I know of no other place!