If you want to buy items off the internet that require credit cards look into pre-paid cards there for everyone I got one for my god-daughter she's 13 and all she has to do is go to a local supermarket and top it up like a phone with a $1.50 extra charge for topping it up.
Don't steal from your parents ever I know very well I've done it before and I have to live with it for the rest of my life its something you'll never get over.
And yes you WILL be caught if you make any kind of purchase what so ever