Votive offerings have been around for ages, often as part of a Christian prayer. In Italy, votives are made of tin or some metal alloy and are in the shape of the subject of the prayer. So if your foot hurts, you would buy and hang a foot on the altar of your saint. If you are concerned about the overall health of a child, you can buy one that depicts a small child. Related reading to learn more: Milagros: Votive Offerings from the Americas and Milagros: A Book of Miracles.
In Mexico, the results of answered prayers often included the commissioning of a special painting called Ex-Voto which depicted saints and interesting misen scenes. They are beautiful, sacred and in some cases bizarre. I love them. Here is a sample: