@ Laura048: My teenage son paid half for his iPhone and I pay the bill. We saved up from the time they were first announced to be able to afford them. My monthly family plan on AT&T isn’t much more than my previous plan was on Verizon. He is responsible for any fees over the monthly rate. We do appreciate being able to afford them, because we have been through tough financial times before.
The content of the text messages does not appear on the AT&T bill, whether in print or online. When you check the account activity, you can see the numbers of those with whom you are exchanging SMS messages.
If your parents wanted to, they could install software on the computer, like Syphone, that logs your texts when you sync your iPhone.
Consider this… your parents love you and want you to be happy and successful in life. They don’t want you to make mistakes like they or their friends may have made at your age. If you are a minor, they have every right to know what you are up to. I hope that your concerns are only because you’d be embarrassed if they read them, and not because you’re doing something potentially detrimental to your health or well-being.