I heard dandruff shampoo is a cheap trick to growing long hair. I don't know if it is true, but I'm desperate to grow my hair and my mom won't let me get extensions. Has anyone ever tried this and it worked for them?
Does anyone have any other tips to grow my hair long fast?

Baloney.
The only way to grow hair long is to wait.
A healthy diet means healthy hair, so that will have some effect, especially on whether you get split ends etc.

No, it doesn't work. Eat your vegetables instead (vitamin A = healthy hair).