If the pyramid quilt was too expensive several years ago, does she think that prices have gone down? By all means, even if she is your oldest and dearest best friend, have her buy ALL materials: top, backing, thread and batting. Then write something up with the price for your labor. Both of you should sign the document and get a copy. It should also state that if she doesn't pay you for your labor, you keep the completed quilt. No refund on what she paid for the materials.