Hey Skorpion, you sound like a great Kid. Listen to your Mother, she has your best interests at heart.
But... if you were to cut some lawns and shovel snow out of some driveways, you could probably earn more than the $15.00 per month to play online. We all work for what we do on our leisure time.
You could send HTC part of that to play...you never know, maybe Mom would be okay with that. Talk to her, she wants you to grow up healthy, strong, and self sufficient. If she sees that you are willing to work for what you want she may surprise you.
At any rate, like I said... you sound like a great kid and it also sounds like you have a great Mom.
Cheers,
RTR