Feeling Used By a Friend

It takes a lot to make me feel used, or something consistent. A neighbor friend of mine has been asking, every Monday for 3 Mondays now, to use my FAX machine.
Well, friendship comes first and feeling used should never happen. So I have decided, after she came by again yesterday, to send her an Email politely explaining how I feel used because of convenience and that I don't want it to become a wedge in our friendship; so she should go to an office store to do her FAXing from now on.
I don't mind favors from time to time and I DO love helping out, but to use me for my FAX because I am 3 doors down in the neighborhood is unacceptable!