How can i help my friend who cuts herself?

my friend Shelby (14) last year started cutting herself. she says its to deal with all the stress at home and that it makes her feel better. i told her that its dangerous etc. but she doesnt listen. her mom doesnt care and her dad left a long time ago. she says im the only one that can help her, yet when i do, she doesnt listen. a counselor is out of the question cause her mom cant afford it. shes even tried killing herself before. what can i do? shes my best friend and i dont want anything to happen to her.