I think that is nice of her but I would offer her 10%, she probably thinks your quilts will be a big draw for her. So I would not feel bad just paying the 10% that way you should feel bad about it.

Have her put the free thing in writing and then give her 10% out of the goodness of your heart.

If she has already purchased from you to sell in the store maybe that is the way to work with it. Whatever agreement you reach with her, I would make sure it is in writing.