My parents won't buy me anything?

i don't have nothing of my own. my 3 sisters and i share everything including a room, clothes and toothbrush. but my parents aren't poor! my mom gets herself everything. just the other day she ordered a hair piece off some shopping channel for 80 pounds and she can't even put it in. she has an iq of about 2 and i'm not being disrespectful, it's the truth. she can't cook, clean and i'm sick of having to cook for my sisters and live in like a tramp. my auntie gave me some of her old earrings and my sister saw her throw them away but she insists she didn't. she tells me to buy my own things but she doesn't give me any money ever and i'm too young to get a job. what can i do?