Help my mother please

I would like to buy my mum a car .my mum has struggled most of her life with bad depression and no one believed in her or stayed beside her . I am too young to stand up for her and I save every single dollar I get just to give it to her . She has no car and she walks every day just to go get me and my siblings food and water, please I need your help. One dollar will make a difference . please it hurts to see her cry everyday and me not being able to do anything about it.