I collect wire from the telephone company and use them with scraps of
fabric collected from moms (or dads who sew) and make animals, like
snakes, wrapped and wrapped in wire and then hung from the ceiling;
I collect end paper from newspapers and graphic printers that can be
rolled out on the floor for murals; the empty cardboard roll in the
middle can be hot glued to a square of masonite plywood (which I have
cut from a 4 X 8 sheet at a building supply compnay) and use cardboard
boxes that kids cut into shapes to add to the cylindars for imaginary
animals - painted with tempera, adding raffia, yarn, etc.
I collect samples of laminate and other materials from paint stores which
can be drawn on with oil pastels, adding beads, sequins, etc. and glued
to a pin back with a hot glue gun for wearable art pins....
I've collected sandblasting tape, cut it into shapes, put it on cardstock
scraps I got free from framing shops and used them for
printing....painting the shapes with tempera and "printing" on paper...
I also go into bookstores that carry art supplies and ask for
donations...$25 will go a long way sometimes....
....uh, hope that helps.