If it was me I would end this friendship, fast. It doesn't matter how close you both have become, once it involves money, it's no longer a good friendship. Some friendship out there may stay strong through a money problem but rarely. I have this 'best friend' since high school, I used to lend her lunch money that she pays if she feels like it, back then I thought it's just a few dollars to get a pie it's nothing, I like to buy my friends stuff once in awhile. Okay so we finished high school and during our uni years she would ask for money for a jacket when we were at the mall cause she forgot her wallet or she hasn't got paid from work) she always promised she will pay back once she gets money but it never happens. She would ask to borrow clothing etc from me but never return as well, she would act whatever is mine is her too. Anyways, my parents taught me that there's no such thing as best friend forever in this world, friends comes and goes, even if you guys become so close like sister, says bestfriends forever, once you guys come across money problem, this friendship is never going to last. I finally ditched this friend of mine earlier this year, after 10 years of friendship, I finally ditched her! I felt released! So let's not make this all about me ~ sorry, I didn't even realized. Your best friend / room mate is not good for you, the longer you keep her around, the more you'll get frustrated everytime you see your car!