I was a little bit reluctant to review these two sites, because they were both originally for the older 18+ teens, but the rules have changed. They are now open to teens 13 and up...
BUT! Be patient, because the earnings are a little bit (actually very much) slow with these two--though they are fun sites to join.
Instant Cash Sweepstakes (ICS)
ICS is one of the simplest sites for teens to make easy money online. At ICS you win tickets, and coins from every survey question that you answer. There are three questions per survey as you can see above so they are pretty simple, and easy to complete. But what do tickets, and coins have to do with anything?