should i be friends with this girl or nt?

Ok so theres this girl that i guess im friends with. And shes really bossy, shes always telling me to buy her stuff, (including dangle earrings and a vera bradley cell phone case). Last year she cyberbullied two of my other friends (threatening texts) so obviously they do not have the best opinion of her. They think i should be mad at her and i guess in some respectsi should be. she has taken my phone and lost it (but she found it pretty quick i just had to beg her to look) and she takes sparring so she always wants to practice with me. The problem is that i dont do any form of martial arts. Shes always showing me how she blocks and she kinda likes to see me fail at blocking her. She accidentally punched me in the nose once (but it barely even bled so no big deal right?) she also accidentally punched me in the jaw once but it barely hurt so its ok right? And she also drags me places by the hair a lot which gets painful and annoying but i can deal. And she sometimes threatens me but i don't think she means it. She insults me a lot but usually not too bad. Although sometimes it does get offensive. For example, when we met, she introduced me to bands like blood on the dance floor and black veil brides. Now she hates both and she constantly calls me a freak for still liking them. I also recently got scene hair, and i thought it looked good, but she said that it looks really bad on me. She is also one of those kids that gets almost whatever piercing she wants, so shes also constantly bragging. I have another friend who thinks shes a ***** and thinks i shouldn't hang out with her. Although she never actually did anything to her, just me sometimes. Back to what i was saying earlier, she constantly asks for favors, and most of the time i do it for her. But her requests have gotten.....more expensive. See, she's not poor, but i go to a pretty expensive private school and she's not quite as well off as everyone else. Now, she somehow thinks i'm rich, both of my parents are teachers- you do the math. So she keeps asking me for things that involve lying to my parents and spending their money. And by the way, i already am lying to my parents by hanging out with her. My mom met her once at the mall and my mom decided that i shouldn't hang out with her. It was a little judgmental of my mom but she was wearing a pin that said "im not antisocial i just hate u". She also keeps telling me to do things that are kind of against school rules. And she wanted to pierce my navel for me. And when i said no she said "can i still poke the hole so i can get more piercing experience?" And by the way she wanted to do it in the school bathroom. And she wanted to do my cartilage too. She thinks she can order me around. How can i show her that i'm not her slave and should i stay friends with her at all?

sorry its long