Swagbucks only lets you earn points once a day on certain types of poll - answer a second poll and you won't get paid. So always read terms and conditions carefully.
Anyone registering for the special offer has 60 days to earn 849 swag bucks. Once you reach this threshold, 1,698 additional swag bucks will be transferred to the 'my gift cards' section of your account within 10 days. You'll then have 2,547 bucks in your account which gets you gift cards at Amazon and the other retailers.
To choose a giftcard, go to the rewards section of your account. Depending on which giftcard you choose, you can either use in-store or online and most are valid for a year.