If your new to doing these GPT sites you should first try out Cashcrate, really user friendly site, its 100% free, and it has a great referral program, and also it has a forum which has a lot of insights. Payout is monthly, and the minimum amount is $20.
This site can be one of your biggest money makers. It has tons of free offers. Many great ways to earn extra money. The minimum amount is $20 via paypal. It's free to join.
This site gives tons of bonuses for doing offers. It's free to sign up. You get $3.00 sign up bonus. Minimum payout is $20. You can really make money on this site.