Got to go "old school" Mike - whatever wood you happen to have, like stir sticks, toothpicks, popsicle sticks. Card stock like business cards (ready made billboard
), packaging, cereal boxes. Plus good old white glue or similar.
You might want to check out the "Robin at his best" sub-forum of the Academy to see what is possible using mostly cerealboard and other "common" materials.
Andrew