I got my misguided 18 y/o niece (DH's side) a job at my office part time. Love her... but damn she drives me nuts...

We are helping her get her life together since she has no parental support. She is saving for a car so for now her boyfriend drops her off at an agreed upon exit by my house and I drive her to the office. She continuously switches the arrangement because the punk boyfriend decides he doesn't feel like driving her. She lives with him and I can tell it is only a matter of time until he ends the relationship (although according to her, they will end up married). I dread that phone call, because she has nowhere else to go (besides our house).

She never packs a lunch or has any money. The other day she "wanted a smoothie." I told her I don't mind packing a yogurt or sandwich for her IF she saves her money for a car, since she looks at us as parents, and she is overall a nice kid, but we won't be buying food out..... she deals with what she gets. I would like a $8 smoothie, too, but unfortunately I deal with my Aldi bagged lunch... she can too.

Today she tells me she "forgot" tampons and needs them ...but has no money on her. Unacceptable... she is too old to forget tampons! I had to buy her a pack, not much else I could do at that point. Today she also tried to ask me to take her all the way to her boyfriend's house because he was busy and couldn't get her. I told her no, and she ended up securing a ride from a friend. Amazing how fast a ride materializes once you say no. :?

She is doing well at the office, she recently got her learner's permit and opened a bank account. I know teens can be selfish and she is still young, but I really want her to learn to take care of herself and not end up like the rest of DH's family (moocher lowlifes with lots o' baby daddies).

Any tips or tricks for dealing with naive teens?