What should i dooo, please help?

i have a best friend outside of school and a best friend in school. but my friend in school always beggs for money and she says she will pay it back and lie that she has payed me back already. she askes for my lunch and we can never go out coz she has no money but ofcourse i stayed her friend coz i wouldnt judge her for the ammount of money she has. then now she always lies and if someone says something like ewwwwwwww she farted to me she would be like ewwwwwww thats discusting when she knows i didnt. whenever i say she has lied and needs to stop otherwise we shouldnt be friends she goes off and talks to someone who she dont like and says ur my best friend. i have other friends but i cant hang around with them coz they have their own friendship groups and i wouldnt want to really. my sister has the bestest friend ever! i have the bestest friend ever out of school but not at high school coz she went to my primary :(