please help a student out

I'm a student with no money and with parents who don't want to give me any either. I've always had to find some way to scrap money together to either buy a new phone when mine broken or even to just watch a movie with friends and then there's my sister who always gets new phones from my parents, always is given money when she goes out and shops. Why does this happen? Obvious favoritism that's why. So please, it would really mean a lot to me if i could just get some help to get a new computer because my old one has a busted battery and cant be charged properly, which in turn leads to very hard nights of trying to complete assignments ( Battery why do you always die on me halfway) Thank you so much in advance to anyone who helps it really means a lot T-T