One of my favorite ways to ways to earn gift cards is Valued Opinions. I signed up with them online earlier this year. They send surveys that take anywhere from a few minutes to an hour+ to complete. I usually work on them when I'm watching TV at night, so it doesn't really take anything away from my day.
The rewards are great. You can earn anywhere from $1+(usually $1.5-4). I heard you can earn up to $50, but I haven't received any of those surveys. Once your account reaches $20 you can request a gift card that will come in the mail. The gift cards to choose from are: Marriott, iTunes, Macy’s, Amazon.com eLUXURY, Fragrancenet.com. I usually choose Macy's cards and get my kids clothes.