You should be grateful for what you have, your parents obviously* don't think you're ready for one because handling it can be a big responsibility & I'm sure they would be the ones paying the bill not to mention, maybe if you really want one then prove to them that you are responsible enough for one, be ready for the consequences, good luck :)
You can get your parents to get you an iPhone 5 by being obedient and going out of your way to please them. In addition, you can also give them valid reasons why you need the phone and how it will add value in your life.
Be obediant,Do something secretly around your house that your parents want done(A chore or something)Get good graded and show off your report card.IPhones are terrible,they are taking over the world.In the end you'll have no freedom.The onlything good about Apple products are the phone cases.You should get something cheap,Nice,and doesn't break as easily as iphones.(Android or windows) these phones have amazing screens that take forever to crack,Gorgeous cameras,and lots of apps in the market.Not to mention that the look actually changes throughout the years unlike iphones.And of course have amazing features.But of course it is YOUR choice.Oh and give them plenty of reasons why you need it. Not want.
Be on your best behavior at all times show that you are responsible. Save for it yourself and let your family know that you will work to help pay for it. Offer to do chores around home and for neighbors