Try taking on responsibilities around the house to show that you are mature enough to have that luxury.
I'm 15 and my parents won't let me have a phone. They say that I haven't earned their trust. How do I convince them and earn their trust?
I didn't get a phone till I was 17. We didn't have the money. I didn't even need it. I would enjoy the time you have without one I hate all the nonsense that comes along with phones. Phones kill traditional relationships. Just be patient youll get one eventually.
The degree to which you’re accorded trust often matches the degree to which you prove yourself trustworthy. Not that you have to be perfect. After all, everyone makes mistakes. Overall, though, does your pattern of behavior give your parents reason to withhold their trust? Likely your parents will accord you greater trust as you build up a record of responsible behavior. Let's illustrate it this way: Imagine a man who owes money to a bank. If he makes payments regularly, he’ll earn the bank’s trust and the bank may even extend more credit to him in the future. It’s similar at home. If you prove trustworthy—even in small things—your parents are likely to trust you more in the future, perhaps in due time with a phone.
Get good marks in school, obey their rules... Help them with some small work, and spend your pocket money smartly.
When I was your age my parents took out the home phone due to my sisters calling long distance their was no cell phones