Here are some list of code for you ! you can get cool stuff from it ! Bit there is no code for free membership i am really sorry about that :(

explorer - 100 gems
ngkidsrox - 1000 gems
discover - 1000 gems
AKBDAY3 - 3RD BIRTHDAY CAKE
bemybuddy- 500 gems
AJHQ300- 500 gems
10million - 10 million banner
ngeplorer-1000 gems
drawing - 500 gems
hooot - 500 gems
alphas - 500 gems
kangaroo - 500 gems
koala - 500 gems
dolphin - 500 gems