Mother daughter problems am I wrong?

Hi me and my step dad are the providers in my home besides from my mother and sister (who still in high school but gets money from child support from her real dad) I always try and buy things for my family but sometimes I like to buy things for my face and hair like care products but my mom calls me selfish and starts going agents me because she wants the same products to I told her I got them because I need them for my acne skin and she screams at me and says “ y’all never wanna huck your mom up with good shit “ but I feel I work hard for my money and I simply got them because I wanted to start taking care of my face because I never do ever, I feel really bad like I don’t deserve to do this or get myself anything good, my mom doesn’t work but My step dad treats her like a queen and buys her whatever she wants, I give her money sometimes as well but she still gets mad and it feels like she wants to be in charge of how I spend my money idk I don’t understand idk if I’m the wrong in this situation, I’m 20 years old