Free Art Materials
Here's something that all moms and teachers should know about...
Frame shops have huge piles of scraps that they will give you for free! Call around and ask for any mat board or foam core scraps that they might have. Usually they will be happy to let you have them! This is an amazing resource for free materials that everyone needs to take advantage of. I use these scraps in so many of my art projects! I would be lost without my pile of freebies from the local framers.
You can also try Print Shops. Quite often they will have usable scraps of posterboard left over from a printing project. Ask them for any ends of paper rolls that they may have. You can find a wide variety of paper and card stock scraps at these places. They are a little harder to find, but well worth the effort.
Call around and see what's available in your area!