NAME THAT BOOK! (one at a time)

A popular high school girl dies near her school because she was hit by a car. her spirit is stuck, but she meets a boy who can see ghosts. she strikes a deal with him, he'll help her resolve her unfinished business, and she'll chase the other ghosts away. she finds out her best friend never liked her, and her boyfriend has been cheating. i dont remember much else, but the girl moves something in the dude's house to help him with his concerned parents.

BUT I NEED TO REMEMBER!