It does seem a bit silly to say you can sell it to her, she pays you $1.00, then it is hers to make a copy for herself, she no longer wants or needs the magazine so she sells it back to you for $1.00. As long as you are not doing it for a profit, you make the extra copy for yourself, oops, you don't want the copy any more so give it to your friend.
It is nice to be concerned but you are not making 15 copies and teaching a class on it. Make the copy and don't worry about it. A friend & I work together all the time to understand a pattern if we are having trouble. I don't feel a need to pay extra for a pattern, or pay the quilt shop where we bought the pattern but didn't sign up for a class. There are too many videos on the internet that are free and we have a good time working together.