TYVEK:: This awesome material (partial leftover roll) was donated to me by a parent associated with the building profession. It works so great for covering countertops and tabletops! You can even wipe it with a lightly damp sponge.
WAX PAPER::I use wax paper in many ways, but my favorite way is to cover my clay storage boards with it after the students glaze their ceramic projects. It's just the perfect width for my boards and the glaze beads up on it to avoid getting underneath the pots.
PLACEMATS:: I use dark-colored construction paper over and over when students are using markers or crayons so that we keep the tables clean. I have larger placemats for painting and oil pastels. I have a flat file full of them, so the kids know right where to go if they need one. The painted placemats are awesome, because they turn out to look like a work of art on their own or you can repurpose them by painting on top of them or cutting them into strips and using them for other projects such as weaving!