Showing appreciation doesn't have to come in the form of a gift. Why not express to her your thoughts on what she does that is kind and helpful to others. Take her to dinner to thank her for all her kindness. Send her a text, email or call her after you find out she has done something kind to another. She sounds like a very generous person and I'm sure she feels unappreciated at times not because she doesn't get a gift in return, but maybe her efforts don't get recognized. We all want to feel appreciated!