You will need to get grocery store ads donated to the classroom. My students brought in enough in just one day to complete this project. They enjoyed working on the project and some of the proportions were quite challenging. It's good for all levels because many of the ads they found were something like "2/$3" or "5/$10." Students who are at a higher level used items like "$4.99 for 32.6 oz" and they found the price per ounce. I had my students find 7 items.