You can be cruel or kind in telling her about your
irritation.
Kind way: Tell her you care for her well being, thus her financial
management (I noe... no link but does she cares?), you prefer for
her to sms you a few times a dae or week so that she can keep it
under control. Or tell her to change to online chatting. MSN, AOL,
IRC, email.
Cruel Way: Ask her who is she to you. Y bother to sms every details
when there are certain lame and redundant stuffs everybody can do?
Tell her not to disturb you unless absolute necessary or ELSE you
ignore her totally. Or better yet, tell her parents.
I would not recommend da cruel wae, IN FACT I dun wan you to come
to dat at all. Only when you find it really, REALLY irritating. I
suggest you be good to her as a friend. Its better to have a friend
than not to have one right? Have a talk with her first. Clarify the
situation and tell her your feelings on the smses. She will
understand if she really treats you as a friend or more.