What can i use to not damage my hair when flat iron it?

Im 13 i have wavy hair. I had already straighten my hair without using anything but a straightener. And i ended up damaging it with a lot of split ends. So i went to get a trim about a month ago. And i hate always having wavy hair. I want my hair straightened without the damage. is there any product that i can put on with no damage after i straighten it.i want answers from people who tried it themselves and it really works. my mom is going to get me a ceramic straightener.is that a good straightener? Is there something i could just leave in my hair and it could just stay straight for school and after school. im going to get an asian mullet for my hairstyle. so please help me if u can. i dont want to keep chopping off my hair.